WO2007119271A1 - Thin-film rare earth magnet and method for manufacturing the same - Google Patents

Thin-film rare earth magnet and method for manufacturing the same Download PDF

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Publication number
WO2007119271A1
WO2007119271A1 PCT/JP2007/000247 JP2007000247W WO2007119271A1 WO 2007119271 A1 WO2007119271 A1 WO 2007119271A1 JP 2007000247 W JP2007000247 W JP 2007000247W WO 2007119271 A1 WO2007119271 A1 WO 2007119271A1
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film
crystal
alloy
rare earth
thin film
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PCT/JP2007/000247
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French (fr)
Japanese (ja)
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Kenichi Machida
Shunji Suzuki
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Namiki Seimitsu Houseki Kabushiki Kaisha
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Priority to JP2008510732A priority Critical patent/JP4988713B2/en
Publication of WO2007119271A1 publication Critical patent/WO2007119271A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F10/00—Thin magnetic films, e.g. of one-domain structure
    • H01F10/08—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers
    • H01F10/10—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition
    • H01F10/12—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition being metals or alloys
    • H01F10/126—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition being metals or alloys containing rare earth metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F10/00—Thin magnetic films, e.g. of one-domain structure
    • H01F10/26—Thin magnetic films, e.g. of one-domain structure characterised by the substrate or intermediate layers
    • H01F10/265—Magnetic multilayers non exchange-coupled

Definitions

  • the present invention relates to a thin film rare earth magnet suitable for micromachines and sensors, small medical and information equipment, and a method for manufacturing the same. More specifically, the present invention relates to a high performance thin film rare earth magnet having a large coercive force and a method for manufacturing the same.
  • Nd_Fe_B rare-earth sintered magnets have very high magnetic properties compared to conventional Ferri magnets, so they have VCM (voice coil motor), MR I (magnetic tomography equipment) Used in various fields such as various motors.
  • the magnets used for these are generally flat or cylindrical shapes with a side of several to tens of millimeters, but mobile phone vibration motors have an outer diameter of 3 mm and a wall thickness of about 1 mm. Cylindrical magnets are used, and smaller magnets are required in the micromachine and sensor fields.
  • powder molding is difficult to produce a sintered body with a thickness of 1 mm or less. Even in the method of cutting and polishing after manufacturing a large sintered body block in advance, it is extremely difficult to obtain a magnet with a thickness of 0.3 mm or less due to problems with magnet strength and production processing technology. .
  • a thin film magnet is sintered by depositing a magnet alloy component on a substrate or a shaft in a vacuum or reduced pressure space and applying heat treatment to appropriately control various conditions.
  • thinner-film magnets are applied to actual devices, smaller devices are often required to have higher-performance magnet characteristics, and the devices can be used stably for a long time in various environments.
  • coercive force 1.5 MAZm or more, preferably 2 MAZm or more, in addition to improving the maximum energy product and remanent magnetization.
  • Fig. 1 shows the temperature dependence of the remanent magnetization (B r) and coercive force (H c j) of a typical N d_F e_B magnet. From Fig. 1, it can be seen that N d_F e_B magnets have the essential problem that the magnetic properties greatly decrease with increasing temperature, and in particular, the rate of decrease in coercive force is large. Therefore, when N d _ F e _B system magnets are used for small motors, etc., the motor temperature easily rises to 60 to 80 ° C due to heat generated from the coil when energized. In order to reduce the influence of the decrease in magnetic properties due to temperature rise to reach hundreds of degrees Celsius, increasing the coercive force at room temperature is an essential issue for industrial applications. .
  • a thin film magnet formed on a substrate such as a flat plate or a shaft grows the C axis of the N d 2 F e 14 B crystal in the thickness direction, and is magnetized in this film thickness direction.
  • the thin film magnet has a thin film thickness of about several tens of meters / m to several tens of meters, and is a few tenths to one hundredth of the length of the four sides of the flat plate and the shaft diameter.
  • Non-Patent Document 2 the remanent magnetization of this thin film is as low as about 0.7 T and the film thickness is 1 m or less. There is a problem in practical use because magnetic flux cannot be obtained.
  • the inventors of the present invention first, from the surface of the N d_F e_B based sintered magnet, N d 2
  • N dF e _ B thin film magnets N d 2 F e 4 B crystal grains are made larger than the single domain grain size, and a grain boundary phase is formed.
  • a thin film magnet with H cj of 1.5 MAZm and excellent magnetism has been obtained (Patent Document 4).
  • Patent Document 5 There is a report example (Patent Document 5) of producing an exchange spring magnet in which Nd-Fe-B and Fe are laminated for a thin film-laminated magnet. As a result, the coercive force is reduced and the N d 2 F e 4 B crystal grain size is less than 1 m. Furthermore, there is a report example of a thin-film magnet in which N d_F e_ B and Ta are laminated (Non-patent Document 3). In this example, the use of Ta improves the orientation of the N d 2 F e 14 B crystal. Therefore, there is no effect of improving the coercive force, and its value is as small as 0.9 MAZm.
  • Patent Document 1 Japanese Patent Laid-Open No. 8-83713
  • Patent Document 2 Japanese Patent Laid-Open No. 11-288812
  • Patent Document 3 JP 2005-011973
  • Patent Document 4 WO 2005/091 31 5 A 1 Publication
  • Patent Document 5 Japanese Patent Laid-Open No. 11-214219
  • Non-Patent Document 1 Journal of Japan Society of Applied Magnetics, 27, 10, 1 007, 2003 Year
  • Non-Patent Document 2 Journal of Applied Physics. Vol. 98, 1 1 3905, 20 05
  • Non-Patent Document 3 IEICE Technical Committee Materials, MAG-03-03, 2003, Invention Disclosure
  • N d 2 F e 14 B compounds have high saturation magnetization and high magnetocrystalline anisotropy, high remanence and relatively large coercive force have been obtained in the form of sintered magnets and thin film magnets.
  • Thin-film magnets are generally composed of N d 2 Fe 14 B crystal grains of approximately 0.3 U m or less, which corresponds to a single domain particle diameter.
  • the raw material alloy has a magnetic anisotropy greater than Nd, such as Dy.
  • the present inventors have determined that the N d_F e_B alloy film and M or M Alloy (However, M is one or more of Pr, Dy, Tb, and Ho) After stacking the films, heat treatment is performed, so that M element partially replaces Nd and becomes solid solution ( N d, M) 2 F e 14 B crystals formed on the surface, N d 2 F ei 4 B3 ⁇ 4i ⁇ ⁇ and N d 2 “ei 4 B crystal grain boundaries (N d, M) 2 In a thin-film magnet composed of a grain boundary phase (or simply called “grain boundary phase”) composed mainly of M element formed in contact with the interface between the e 14 B strand and the B crystal, the decrease in residual magnetization is extremely small and maintained. It has succeeded in providing a thin-film magnet with a remanent magnetization of
  • the present invention is as follows. (1) M or M alloy (where M is one or more of Pr, Dy, Tb, and Ho) Three layers in which films and Nd_Fe_B alloy films are alternately stacked A thin-film rare earth magnet obtained by heat-treating the above laminated structure and interdiffusing the M or M alloy component and the Nd-Fe-B alloy component,
  • the heat element M by the surface portion of the Li N d 2 F e 4 B crystal grains process is dissolved by replacing the N d (N d, M) 2 F e 14 B crystals are formed, and N d
  • N d A thin film rare earth characterized in that a crystal grain boundary phase made of M or M alloy is formed at the interface of (N d, M) 2 F e 14 B crystal at the grain boundary of 2 F e 14 B crystal grain magnet.
  • N d 2 F e 14 B crystal phase is formed in layers in the thickness direction of the thin film, and the (N d, M) 2 F e 14 B crystal is in contact with the interface between the crystal phases.
  • N d 2 F e 14 B crystal phase is formed in layers in the thickness direction of the film, around the N d 2 F ei 4 B Yui ⁇ Yo (N d, 2 F "e 14 B crystal and an interface A thin film rare earth magnet as described in (1) above, wherein a grain boundary phase made of M or an M alloy surrounding N d 2 F "e 14 B crystal grains is formed.
  • the N d_F e_B alloy is composed of an N d 2 F e 14 B compound, the content of M element in the thin film is 1 to 30% by mass, and the total content of N d and M element
  • N d_F e_B alloy and M metal or alloys thereof by physical film-forming method in a vacuum container are alternately laminated, and then heat-treated at 700 to 1100 ° C to mutually diffuse the M or M alloy component and the N d _Fe _ B alloy component.
  • the element M is substituted with N d to form a solid solution (N d, M) 2 F e 14 B crystal on the surface of the N d 2 F e 14 B crystal grains, and N d 2 F
  • N d, M solid solution
  • a grain boundary phase composed of M or an M alloy is formed at the grain boundary of e 14 B crystal in contact with the (N d, M) 2 F e 14 B crystal interface.
  • N d _ F e-B alloy film is 0.05 m to 50 m, and the film thickness ratio of N d _ F e _B alloy and M metal or its alloy is 99 : 1-60
  • an N d_F e_B film and an M metal such as Dy or an alloy thereof are alternately stacked to form an M metal or an M alloy as N d -F e.
  • an M alloy such as Dy or an alloy thereof
  • thermal diffusion to _ B based film around part of a solid solution by substituting the N d to N d 2 F e 4 B crystal grains formed, many of the remainder the crystal grains of the element M
  • a grain boundary phase is formed between the Z and N d 2 F e 14 B crystal phases.
  • a part of N d that easily diffuses in the N d_F e_B film diffuses into the M metal or M alloy film.
  • this crystallographic structure involves 600 ⁇ 50 ° C and 700 ° C, which causes crystallization and improved orientation and diffusion of M element in a state where the thin film magnet is highly oriented perpendicular to the substrate. It is desirable to perform two-stage heat treatment in the high temperature region of ⁇ 1100 ° C, more preferably 900 ⁇ 1100 ° C, which is larger than the conventional single domain grain size (0.3 m) of N d 2 F e 14 B. N d 2 Fe 14 B crystal grains of about 5 m to 30 m, more preferably about 1 m to 5 m are formed by heat treatment to have a magnetization mechanism similar to that of a sintered magnet. It has the effect of improving magnetism, which is important for attaching thin film magnets to equipment.
  • FIG. 1 is a diagram showing the relationship between the magnetic properties and temperature of an N d-F e _B magnet.
  • FIG. 2 is a schematic diagram showing the structure of the crystal phase, crystal grains, and grain boundary phase of the thin film rare earth magnet of the present invention.
  • A Floor plan
  • B A cross section in the film thickness direction
  • FIG. 3 Drawing SEM image of the sample (6) of the present invention.
  • FIG. 4 X-ray diffraction patterns of the sample of the present invention (3) and the comparative sample (1).
  • FIG. 6 is a relationship diagram of magnetic characteristics with respect to film thickness of the samples (24) to (30) of the present invention and the samples of comparative examples (12) to (13).
  • the thin-film magnet targeted by the present invention is made of an N d_F e_B alloy, and generally consists mainly of an N d 2 Fe 14 B crystal phase containing N d, F e, and B as essential component elements.
  • Nd used for alloy production may contain other rare earth elements such as Ce and Pr as impurities or up to about 5% by mass to reduce raw material cost. It also contains inevitable impurities derived from thin film constituent materials and film formation and heat treatment processes.
  • the N d 2 F e 14 B crystal grains of the thin film magnet such as for or Curie temperature toward the upper to miniaturization, a portion of the F e components Co, N i, T i, V, C Replacement with one or more elements of r, Cu, AI, Zn, Ga, V, Mo, Nb, Ta, W is performed.
  • the amount of substitution for Fe varies depending on each element.
  • Cu and Mo are effective for uniformizing and refining the grain size with a substitution amount of about 1% by mass. The effect of improving the Curie temperature by about 100 ° C with a mass% substitution amount.
  • N d_F e_B rare earth alloys cannot avoid the incorporation of impurities such as oxygen and carbon during raw material refining, film formation, and heat treatment. It is beneficial.
  • the M element in the M or M alloy crystal phase laminated with the N d 2 F e 14 B crystal phase is guaranteed to be one or more of Pr, Dy, Tb, and Ho. Necessary for improving magnetic force. The reason is that the magnetocrystalline anisotropy of the R 2 F e 14 B compound when R is a rare earth element is greater than when R is N d when R is Pr, Dy, T b, and Ho.
  • M elements are a single M metal and M alloy, that is, alloys obtained by mixing two or more of Pr, Dy, Tb, and Ho that can be obtained by using various film forming methods, and M metal and An alloy with other elements such as Fe and Co, and containing an M element of about 10% by weight or more, preferably about 50% by weight or more, can be used in consideration of magnetic properties and corrosion resistance.
  • the basic structure of the thin film targeted in the present invention has a structure in which N d 2 Fe 14 B crystal phases and M or M alloy crystal phases are alternately laminated in the thickness direction of the thin film. It is essential that each layer has one layer on the front and back, or one layer on the front and back, and the former has at least three layers each on the front and back. Even hundreds of layers are acceptable.
  • FIG. 2 is a schematic diagram showing a typical example of a thin film configuration.
  • 2 (a) is a thin film of perspective, (b) the thickness direction of the A cross-sectional view of a thin film, (c) is a plan view of the N d 2 F e 14 B crystal phase portion of the lower surface B.
  • an Nd_F6_8 film with a thickness of 1 m to 2 m and a 1 ⁇ 1 film with a thickness of 0.1 m to 0.2 were laminated and a thin film with a total thickness of 50 was heat-treated. It is a schematic diagram in such a case.
  • the number of crystal grains is about one per layer in the thickness direction of the film, but if the thickness of the N d_F e_B film is 10 m, for example, several N d 2 F e 14 in the thickness direction In this case, the coercive force and c-axis orientation are slightly reduced. If the N d_B_F e system film and M metal or M alloy film are alternately formed, each film consists of amorphous or fine crystals of 1 fjl m or less, but after heat treatment, it is shown in Fig. 2 (b) and Fig. 2 ( c) As shown in Fig.
  • N d 2 F e 14 B crystal grain 1 is surrounded by a grain boundary phase 2 made of M metal or M alloy, and the surface portion of N d 2 F e 14 B crystal grain 1 is
  • the M component of the M metal or M alloy is (Nd, M) 2 Fe 14 B crystal 3 in which the M component is mutually substituted and partially dissolved.
  • Figure 2 (c) shows a structure in which N d 2 F e 14 B crystal grains 1 are arranged almost randomly.
  • the lower and upper diagrams in Fig. 2 (b) show the stacking of N d 2 F e 14 B crystal grains 1 respectively.
  • the structure of the thin film consists of a grain boundary phase 2 made of M metal or M alloy upward from the lower layer, N d 2 F e 14 B crystal grain 1, M metal or M alloy. It has a five-layer structure consisting of grain boundary phase 2, N d 2 Fe 14 B crystal grain 1, crystal grain boundary phase 2 made of M metal or M alloy.
  • FIG. 2 (b) shows that the M metal or M alloy film is relatively thin, and the amount ratio of N d 2 F e 14 B and (N d, M) 2 F ei 4 B to the total film thickness is
  • This shows a structure in which the grain boundary phase 2 made of M or M alloy is arranged between the layers of the N d 2 F e 14 B crystal phase, and N d 2 F e 4 B and the total film thickness
  • the upper diagram of FIG. 2 (b) shows a structure in which a grain boundary phase 2 made of M or an M alloy is arranged around the N d 2 F e 14 B crystal grain 1 and between the crystal phases.
  • the lower limit of the content of Nd and M elements is 26.7% by mass and at least 0.3% by mass, that is, about 27% by mass. % Or less, and below that, the grain boundary phase composed of M metal or M alloy becomes relatively very thin, or Of-Fe precipitates in the thin film. It becomes substantially difficult to obtain a coercive force improving effect.
  • N d_F e_B system or a small amount of N d Ritsuchi grain boundary phase by the N d amount of 27 mass% or more in the film is formed around the N d 2 F e 14 B crystal grains, or M
  • a small amount of Nd coexists in the grain boundary phase made of metal or M alloy.
  • the improvement rate of the coercive force is only a few percent, and the effect of the present invention is extremely small.
  • the coercive force is greatly improved as the M element content in the entire thin film is increased by increasing the film thickness of the M metal or M alloy film relative to the N d_F e_B film.
  • the total content of Nd element exceeds 450/0, and the residual magnetization is greatly reduced as described above, so the content of M element in the entire thin film is 1 It is necessary to make it -30 mass%.
  • the average crystal grain size needs to be in the range of 0.5 m to 30 m, and in order to obtain a large coercive force, it is more preferably 1 m to 10 m.
  • the average crystal grain size is determined from the average size of the crystal cut from multiple directions.
  • N in which the Tb element of the sample of the present invention (6) is partially dissolved.
  • the d 2 F e 14 B crystal has a crystal grain size of approximately 2 m when viewed from the SEM (scanning electron microscope) image of the thin-film fracture surface in Fig. 3.
  • the crystal grain size was 3 m to 4 m. Therefore, since it is difficult to accurately measure the irregular crystal grain size in the thin film, in this specification, it is within the range of 50 m ⁇ 50 m at any part of the crystal observed in the film cross section or in the film surface.
  • the average size of the diameters of all crystal grains is expressed as the average crystal grain size.
  • the effect of the present invention can be sufficiently exerted when the thickness of the thin film rare earth magnet of the present invention is in the range of 1 m to 300 m. Less than Nd 2 F e 14 B crystal phase is formed only in the thickness direction of the thin film, and M around the N d 2 F e 4 B crystal grain and / or between the crystal phase M Alternatively, it is difficult to form a structure in which grain boundary phases made of M alloy are arranged, and the coercive force required for application as a machine or sensor in various application devices is insufficient.
  • the thickness of the film is preferable for increasing the coercive force.
  • the thickness exceeds 300 m, the orientation of the crystal deteriorates between the lower and upper portions of the thin film, and the residual magnetization decreases, and There is a problem that the smoothness of the thin film surface is deteriorated, and that the film forming operation needs to be operated for a long time of about 1 mm or more.
  • a thickness of more than 300 m can be obtained relatively easily by cutting and polishing the sintered magnet, so that the thickness exceeding this thickness has a small advantage in producing a thin film magnet. More preferably, it is in the range of 10 m to 300 m, more preferably in the range of 20 m to 200 m.
  • a so-called physical film forming method in which an element component constituting a thin film is formed on various base materials in a vacuum container can be used. Specific methods include vapor deposition, sputtering, ion plating, laser deposition, CVD, and coating in which fine alloy powder particles are applied or sprayed. These physical film formation methods are suitable as a film formation method for Nd_Fe_B-based thin films because a high-quality crystalline film can be obtained with few impurities.
  • Nd_Fe_B By preparing each target of alloy and Dy metal and transferring or rotating the base material or target, N d_F e_B film and Dy film can be alternately formed to obtain a film having a laminated structure .
  • the thickness of the former layer is more preferably about 0.05 m to 50 m. Is about 0.3 m to 10 m , and the film thickness ratio of the former and the latter is preferably 99: 1 to 60:40, and more preferably 97: 3 for obtaining a high coercive force while maintaining high remanent magnetization. ⁇ 75: 25, more preferably 95: 5 to 85:15.
  • each film is a base material ZDy / N d_F e_B / Dy or a base material ZN d_F e_B / Dy / N d_F e_B, and the number of laminations can be arbitrarily set to several to several hundred times.
  • the base material for forming the thin film various metals, alloys, glass, silicon, ceramics and the like can be selected and used. However, in order to obtain the desired crystal structure, it is necessary to perform heat treatment at a high temperature of 600 ° C or higher, and ceramics and metals with relatively high melting points such as Fe, Mo, and Ti are selected as the metal substrate. It is desirable to do this.
  • the demagnetizing field applied to the thin film magnet is reduced, so that the use of magnetic metals and alloys such as Fe, magnetic stainless steel, and Ni is also suitable.
  • a ceramic substrate is used, the resistance to high-temperature processing is sufficient, but the adhesion to the Nd_Fe_B film may be insufficient, and as a countermeasure, a base film such as Ti or Cr is provided. In many cases, these base films are effective even when the base material is a metal or an alloy.
  • N d -Fe-B single-layer films formed by sputtering or the like are usually composed of amorphous crystals or fine crystals of about several tens of nanometers. Therefore, conventionally, to obtain 500 to 650 ° C low-temperature heat treatment by crystallization and crystal growth by promoting an average grain size of 0.5 about 3 m of N d 2 F e 14 B crystal phase.
  • the M element of the M or M alloy film enters the N d 2 F e 14 B crystal grains. Is diffused and substituted with N d to form a solid solution, and the grain boundary phase made of M or an M alloy is surrounded by and / or around the N d 2 F e 14 B crystal grains.
  • the M element diffuses into the N d 2 F e 14 B crystal grains and replaces a part of the N d element, and at the same time, the N d component dissolves with the M element of the M or M alloy film. Diffusion proceeds in the laminated film. If it is less than 100 ° C, it takes several tens of hours to diffuse the M element, which is not practical and it is difficult to obtain a desired crystal structure. When the temperature exceeds 700 ° C, diffusion of M element into N d 2 F e 4 B crystal grains, growth of N d 2 F e 14 B crystals, and generation of crystal grain boundary phases consisting of M or M alloys proceed.
  • the heat treatment temperature is preferably 700 to 110 ° C.
  • the heat treatment needs to be performed in a vacuum or non-oxidizing atmosphere to prevent oxidation of the thin film surface.
  • a heating method a method of loading a thin film sample into an electric furnace, infrared heating or laser Rapid heating and cooling method by irradiation, and thin A Joule heating method for directly energizing the membrane can be appropriately selected and employed.
  • the film formation and the heat treatment separately because it is easy to control the crystallinity and magnetic properties of the thin film, but the substrate is heated to a high temperature during the sputtering.
  • the temperature during film formation at 400 ° C or higher, preferably 700 ° C or higher by increasing the output during film formation, the desired crystal structure can be created. It is.
  • the N d_F e_B film is easily rusted, it is common to form a corrosion-resistant protective film such as Ni or Ti after film formation or after heat treatment.
  • RF sputtering equipment decompression vessel (chamber one) N d_F e_B alloy A disk target is attached to the upper part, and two Mo substrates are placed on the SUS flat plate with a built-in heater on the lower side. Arranged side by side. After evacuating the inside of the sputtering apparatus to the 5 X 1 0- 5 P a, the reactor was kept in pressure by introducing A r gas to 1 Pa
  • the Mo substrate is reverse-sputtered to remove the surface oxide film, and then the heater was heated to maintain the temperature of the SUS flat plate surface at 400 ° C, and an RF output of 20 OW and a DC output of 30 OW were applied to form a 6 m thick N d _ F e _ B single layer film. .
  • the obtained monolayer film was taken out from the chamber.
  • N d _ F e_B alloy A disk target and T b target are mounted facing each other at 180 degrees, and each target is rotated alternately. Then, successively, T b with a thickness of 0.2 m and N d-F e _B with a thickness of 1.8 tl m were repeatedly formed, and T b / N d _ F e_B / T b / N d _ F A multilayer film of e_B / T b / N d _F e_B / T b with a total thickness of 6.2 m was manufactured. The obtained laminated film was taken out from the chamber.
  • the monolayer film and the laminated film obtained by the above method were loaded into a tubular electric furnace, and each was heat-treated for 10 minutes in an Ar gas stream maintaining an oxygen concentration of 5 ppm or less. It was.
  • the heat-treated sample (2) at 800 ° C was subjected to low-temperature heat treatment at 550 ° C, 600 ° C and 650 ° C for 30 minutes each, and a predetermined heat treatment at that temperature (800 ° C, 10 ° C). (2 '). (2' ') and (2' '') were also prepared.
  • Table 1 shows the film formation, heat treatment conditions, and magnetic properties.
  • Samples (1) to (5) of the present invention were heat-treated at 700, 800, 900, 1000, and 1100 ° C, respectively.
  • the heat treatment for crystallization can be performed at 400 ° C. to 650 ° C., but 600 ° C. is preferable from the viewpoint of improving the distribution in the C-axis direction.
  • each sample was measured using a superconducting VSM (vibrating sample magnetometer) and applying a magnetic field of ⁇ 6 T perpendicular to the film surface. Thereafter, the alignment direction of performing X-ray diffraction N d 2 F e 14 B crystals of each sample, and the multilayered sample was examined solid solution state into N d 2 F e 14 B crystal grains of T b element . Furthermore, after lightly etching the surface of each sample with alcoholic nitrate, the film surface was observed with a scanning electron microscope (SEM), and the average crystal grain size was determined from the image by the measurement method described above.
  • SEM scanning electron microscope
  • Table 2 shows the relationship between the heat treatment temperature, average crystal grain size, and magnetic properties of each sample.
  • the average crystal grain size is 0.1 m
  • the coercive force is 784 k AZm
  • the residual magnetization is 1 29 T showed.
  • the comparative sample (1) and the comparative sample (2) obtained by heat-treating the N d_F e_B single layer film are both single-domain of the N d 2 F e 14 B compound with an average grain size.
  • the coercive force was as low as around 700 k AZm, close to 0.3 m corresponding to the particle size.
  • the average crystal grain size of the N d 2 Fe 14 B compound is 0.5 m to 28 m by the high-temperature heat treatment.
  • the coercive force is 1 060 k due to the partial solid solution of the Tb element in the N d 2 F e 14 B crystal grains and the formation of a grain boundary phase mainly composed of T b.
  • the value of the sample of the present invention (3) was 1 730 kA / m, which was 2.4 times that of 724 kA / m of the comparative sample (1).
  • the residual magnetizations of the samples (1) to (5) of the present invention are 1.26 to 1.32T, which is not lower than that of the comparative sample (1), the Tb element Most of them are considered to contribute mainly to the formation of the grain boundary phase without being dissolved in the N d 2 F e 14 B crystal grains.
  • the reason why the decrease in remanent magnetization is small or slightly increased is that the decrease in remanent magnetization is suppressed as a result of the improvement in the squareness of the demagnetization curve as the coercive force increases significantly. .
  • FIG. 4 shows the X-ray diffraction patterns of the comparative sample (1) and the inventive sample (3).
  • the position of the diffraction peak on the (006) plane of N d 2 F e 14 B when the C U-KQ? Line is applied to the sample surface is 44.4 degrees in the comparative sample.
  • the sample of the present invention is shifted to 44.7 degrees. this is
  • T b I N d of Li atomic radius forms a solid solution by substituting a part of the N d atoms N d 2 F e 4 B grains, diffraction lines at high angle side shrinks crystal lattice This means that the Tb element in one of the Tb films in the multilayer film has caused a diffusion reaction with the other NdF e-B film.
  • Nd and Tb element contents (% by mass) in the thin film were determined according to the comparative sample (1) for the monolayer film and the comparative sample (3), and the inventive sample (3 ) was measured by X-ray fluorescence analysis, and the results were as follows.
  • a single layer film of N d_F e _ B alloy with a thickness of 3 m was fabricated as a comparative sample 6 in the same manner as in Example 1 except that the RF output was changed to 15 OW and the DC output was changed to 25 OW. Further, in the same manner, a Tb metal having a thickness of 0.2 m and an N d_F e_B alloy having a thickness of 0.8 m were repeatedly formed as Sample 6 of the present invention, and T b / N d -F eB / T A multilayer film of b / N dF eB / T b / N dF eB / T b was fabricated.
  • the obtained monolayer film and laminated film are loaded into a tubular electric furnace, respectively, and Ar gas Heat treatment was performed for 10 minutes in the air stream.
  • the film formation and heat treatment conditions are shown in Table 3.
  • the magnetic properties of the sample obtained in the same manner as in Example 1 were measured by VSM, and the average crystal grain size was measured by SEM.
  • Table 4 shows the relationship between the average crystal grain size of each sample and the magnetic properties. From Table 4, the present invention samples (5) to (7) have higher coercive force and larger energy volume than the comparative sample (6). It has been clarified that even if any of Tb, Dy, and Pr is laminated, the magnetic properties are greatly improved.
  • N d_F e- B alloy (alloy A) target used in Example 1 the internal pressure of the device is 3 Pa, the temperature of the SUS flat plate surface is 350 ° C, and 3 “output is 100, DC output is A 25-m-thick N d_F e_B single-layer film was fabricated in the same manner as in Example 1, except that 25 OW was used, and 90% D y _ 1 0 instead of the T b target used in Example 1.
  • Alloy target with% Co composition (unit: mass%)
  • Dy_Co metal with a thickness of 0.01 m to 0.8 m and Nd-Fe_B alloy with a thickness of 2 m were sequentially deposited 10 times each, and Dy_Co and Nd A multilayer film of _F e _B was manufactured.
  • the obtained single-layer film and a laminated film was loaded into a vacuum furnace which is evacuated below each 2 X 1 0_ 4 P a, a heat treatment was carried out for 30 minutes.
  • Table 5 shows the film formation and heat treatment conditions.
  • a heat-treated single layer film was used as a comparative sample (7).
  • the Dy-Co film thickness is 0.0 1, 0, 02, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8 m.
  • the comparative sample (8), the inventive samples (9) to (14), and the comparative sample (9) were used.
  • the magnetic properties of each sample were measured by VSM, and the contents of Nd and Dy were determined by fluorescent X-ray analysis.
  • Table 6 shows the N d _F e _B / D y _C o laminated sample with respect to the D y—Co film thickness.
  • Example 5 shows a graph of the relationship between the magnetic properties and the Dy—Co film thickness in comparison with the N d — F e — B single layer film sample. From Table 6, it can be seen that compared to the single layer film comparative sample (7), the laminated film samples (9) to (14) have a significantly increased coercive force due to the introduction of Dy and a decrease in residual magnetization. It became clear that it was small, and it was found that good magnetic properties could be obtained not only with Dy metal but also with Co. However, the comparative sample (8) with a very thin D y—Co film of 0.01 m did not show an effective increase in coercive force because the Dy content was less than 1% by mass. . In addition, the comparative sample (9) whose Dy_Co film thickness is too thick exceeded 30% by mass in the preferred Dy content range, and the total content with Nd also exceeded 45% by mass. And the increase in coercive force stagnated.
  • a disk-shaped alloy target with 28% N d _1.0% B—balance Fe (unit: mass%) with a diameter of 4 Omm Co, Cr, Cu, AI, V, and Nb metal pieces, each of which is a square piece with a side of 5 mm on the alloy target, are selected as appropriate. Then, a predetermined number was loaded. Also, a Ta substrate 8 mm long, 5 mm wide, and 0.3 mm thick after solvent degreasing and acid cleaning was fixed on the alumina substrate using a mounting jig.
  • the N d: Y AG laser was irradiated to the N d_F e_B target to produce a single layer film on the Ta substrate.
  • the obtained monolayer film was taken out from the chamber.
  • the Nd_Fe_B target loaded with the Tb target and Cu metal pieces was irradiated with laser alternately for a predetermined time to dissociate and release the Cu element, and a laminated film was produced on the Ta substrate.
  • the obtained laminated film was taken out from the chamber.
  • the metal pieces were sequentially changed to AI, V, Nb, Cr, and Co, and a laminated film was fabricated on the Ta substrate.
  • the addition amount was adjusted according to the number of metal pieces used. For example, the amount of added metal In the case of 2% by mass, one metal piece was used, and in the case of 5-6% by mass, 3 metal pieces were used.
  • the distance between the target and the substrate is 25 mm
  • the laser output is constant
  • T b is 0.3 m
  • N d_F e_B-X where X is Co, C r, Cu
  • the additive metal selected from AI, V, Nb, and W was 1 m, each layer was stacked to form 20 layers, and finally Tb was formed to produce a total of 21 layers.
  • Table 8 shows the magnetic characteristics when the single-layer film and the laminated film containing the additive metal are heat-treated. From Table 8, the sample of the present invention (15) to (23) of the laminated film is approximately 2 to 3 times the coercive force even when each additive metal is introduced, compared with the comparative sample (10) of the single layer film. Part of the added metal is dissolved in the N d 2 F e 14 B crystal grains, and the other is dissolved in the grain boundary phase, or a coercive force is formed by forming a compound. It is presumed that this was effectively improved.
  • the sample containing Co shows a sufficiently large value although it has a slightly smaller coercive force than other additive metals, and improves the Curie temperature as another effect.
  • the Co content is about 35% by mass as in the comparative sample (11)
  • the coercive force decreases greatly, so the content of these added metals is preferably within a range not exceeding 30% by mass.
  • the reason why the values of remanent magnetization in Table 8 are all less than 1 T is that Nd 2 Fe 14 B crystals are isotropically dispersed in the film as a result of X-ray diffraction analysis of each sample. This is probably because the Ta substrate during film formation was not heated.
  • an alumina shaft having a diameter of 0.6 mm and a length of 12 mm was used as a base material.
  • a known three-dimensional sputtering apparatus was used as the sputtering apparatus. The configuration and principle of this three-dimensional sputtering apparatus are disclosed in Japanese Patent Publication No. 2004-304038.
  • a Cu coil for high frequency generation was placed in the middle of the opposing Tb target, and an Nd_Fe-B target and a Cu coil were also placed in the right chamber.
  • An alumina shaft was attached to the tip of the motor rotating shaft extending from the left side to the right side.
  • the shuff rod is first positioned at an intermediate position between the opposing Tb targets, and a film having a thickness of 0.2 is formed under the same rotational speed and film deposition output as those of Comparative Example Sample 12.
  • Bow I then the motor mounting rod is automatically moved to the right to position the shaft N in the middle of the N d_F e_B target, and a 0.8 m thick N d _F e_B film is deposited,
  • the shaft was again transferred to the left to form a 0.2 m thick Tb film to produce a laminated film with a total thickness of 1.2 m.
  • the number of layers was increased by the same method, and each layered film with total thickness of about 5, 10, 40, 80, 160, 280, 360 m was manufactured.
  • the heat treatment of the laminated film is made according to the samples of the present invention (24) to (30) in the order of film thicknesses of 1.2, 5, 10, 40, 80, 160, 280 m.
  • the sample with m was used as a comparative sample (13).
  • the deposited cylindrical shape The magnetic properties were measured by VSM while sweeping the magnetic field in the radial direction of the sample.
  • Figure 6 shows the relationship of the magnetic properties with respect to the total film thickness of single-layer films and laminated films. From Fig. 6, regarding the film thickness of 80 m, the decrease in the remanent magnetization in the sample of the present invention (2 8) of the laminated film is different from the comparative sample (1 2) of the single layer film indicated by the black mark in the figure. Even slightly, the coercive force increased significantly.
  • all of the samples (24) to (30) of the present invention have a high coercive force while maintaining a relatively high remanent magnetization, and are sufficiently applicable for driving micro motors and the like. Magnetic properties were obtained. However, when the total film thickness is 3600 m, a decrease in crystallinity and a decrease in magnetic properties due to disorder of crystal orientation are observed. Therefore, the total thickness is preferably set to 300 m or less.
  • the present invention provides a thin film permanent magnet having a desired high coercive force and high performance based on the above-mentioned strong demand.
  • the device By being mounted on various application devices such as a micromachine, the device has a high output and a small size. It greatly contributes to the realization of heat-resistant stability in various usage environments based on high coercive force characteristics.
  • the thin film permanent magnet of the present invention can obtain a high coercive force and, at the same time, a crystal phase composed of N d 2 F e 14 B crystal grains having a relatively large crystal grain size and / or around the crystal grains.
  • the magnetic structure is improved by the composite structure of the grain boundary phase of M or M alloy existing between the crystal phases, and the use in the applied equipment becomes easy.

Abstract

This invention provides a thin-film rare earth magnet that has significantly increased magnetic coercive force while suppressing a lowering in residual magnetization of the thin-film magnet. This magnet is a 1 μm to 300 μm-thick thin-film magnet manufactured by heat treating a laminated structure having a multilayer structure. In this structure, an M or M alloy layer, wherein M represents one or at least two of Pr, Dy, Tb and Ho, and a 0.05 μm to 50 μm-thick Nd-Fe-B-base alloy layer have been alternately stacked on top of each other to form a multilayer structure of three or more layers. Upon the heat treatment, the M or M alloy component and the Nd-Fe-B-base alloy component have been mutually diffused. Further, upon the heat treatment, an (Nd, M)2Fe14B crystal is formed on the surface part of Nd2Fe14B crystal grains. The (Nd, M)2Fe14B crystal has been produced as a result of replacement of Nd with element M and dissolution of the replaced Nd in solid solution. Further, a crystal grain boundary phase of M or M alloy is formed in the boundary of Nd2Fe14B crystal grains so that the interface of the M or M alloy phase is in contact with the (Nd, M)2Fe14B crystal.

Description

明 細 書  Specification
薄膜希土類磁石及びその製造方法  Thin film rare earth magnet and method for manufacturing the same
技術分野  Technical field
[0001] 本発明は、 マイクロマシンやセンサ、 及び小型の医療，情報機器向けに適 する薄膜希土類磁石及びその製造方法に関する。 さらに詳しくは、 保磁力の 大きな高性能薄膜希土類磁石及びその製造方法に関する。  The present invention relates to a thin film rare earth magnet suitable for micromachines and sensors, small medical and information equipment, and a method for manufacturing the same. More specifically, the present invention relates to a high performance thin film rare earth magnet having a large coercive force and a method for manufacturing the same.
背景技術  Background art
[0002] N d _ F e_B系の希土類焼結磁石は、 従来のフェライ卜磁石と比較して 非常に高い磁気特性を有するために、 VCM (ボイスコイルモータ） 、 MR I ( 磁気断層撮影装置） 、 各種のモータ他、 様々な分野で使用されている。 これ らに用いる磁石は、 一般に、 一辺が数 mm〜数十 mmの大きさをもつ平板や 円筒形状をしているが、 携帯電話用振動モータには外径 3 mmで肉厚が約 1m mの円筒状磁石が使われ、 さらに小型の磁石がマイクロマシンやセンサ分野 において要求されている。 しかし、 厚さが 1 mm以下の焼結体を製作するに は粉末成形が困難である。 また、 予め大きな焼結体ブロックを製作した後に 切断や研磨を行う方法においても、 磁石強度や生産加工の技術上の問題によ リ 0. 3 mm以下の厚さの磁石を得ることが極めて難しい。  [0002] Nd_Fe_B rare-earth sintered magnets have very high magnetic properties compared to conventional Ferri magnets, so they have VCM (voice coil motor), MR I (magnetic tomography equipment) Used in various fields such as various motors. The magnets used for these are generally flat or cylindrical shapes with a side of several to tens of millimeters, but mobile phone vibration motors have an outer diameter of 3 mm and a wall thickness of about 1 mm. Cylindrical magnets are used, and smaller magnets are required in the micromachine and sensor fields. However, powder molding is difficult to produce a sintered body with a thickness of 1 mm or less. Even in the method of cutting and polishing after manufacturing a large sintered body block in advance, it is extremely difficult to obtain a magnet with a thickness of 0.3 mm or less due to problems with magnet strength and production processing technology. .
[0003] 一方、 最近、 スパッタリングゃレーザーアブレーシヨン等の物理的成膜法 により、 厚さが 0. 3mmよりも薄い磁石が製作されるようになり、 従来の 磁石よリも厚さが薄いので j薄膜磁石と称され、 最大エネルギー積 (BH)maxが 200 k JZm3、 残留磁化が 1丁、 保磁力 H c jが 1 MAZm以上の特性の 磁石が報告されている （例えば、 非特許文献 1、 特許文献 1 ) 。 [0003] On the other hand, recently, magnets thinner than 0.3 mm have been manufactured by physical film-forming methods such as sputtering laser ablation, etc., and thinner than conventional magnets. Therefore, it has been reported as a magnet with the characteristics that the maximum energy product (BH) max is 200 kJZm 3 , the residual magnetization is 1 and the coercive force H cj is 1 MAZm or more (for example, non-patent literature) 1, Patent Document 1).
[0004] これらの製法によれば、 磁石合金成分を真空又は減圧空間内で基板や軸上 に堆積させて熱処理を施し、 各種条件を適切に制御することにより、 薄膜状 の磁石を焼結法と比べて比較的簡単なプロセスで得ることができる。 しかし 、 薄膜磁石を実際の機器に応用する場合には、 小型の機器ほど高性能な磁石 特性が要請されることが多く、 機器の様々な環境での長期間における安定使 用を保証するには、 最大エネルギー積や残留磁化の向上とともに、 特に保磁 力を 1. 5MAZm以上、 好ましくは 2 MAZm以上にすることが強く求め られている。 [0004] According to these manufacturing methods, a thin film magnet is sintered by depositing a magnet alloy component on a substrate or a shaft in a vacuum or reduced pressure space and applying heat treatment to appropriately control various conditions. Can be obtained by a relatively simple process. However, when thin-film magnets are applied to actual devices, smaller devices are often required to have higher-performance magnet characteristics, and the devices can be used stably for a long time in various environments. In order to guarantee the use, there is a strong demand for coercive force of 1.5 MAZm or more, preferably 2 MAZm or more, in addition to improving the maximum energy product and remanent magnetization.
[0005] 図 1は、 一般的な N d_F e_B系磁石の残留磁化 （B r) と保磁力 （H c j ) の温度依存性を示したものである。 図 1より、 N d_F e_B系磁石 は温度の上昇によって磁気特性が大きく低下する本質的な問題をもっておリ 、 特に保磁力の低下率が大きいことがわかる。 したがって、 N d _ F e _B 系磁石を小型モータ等に使用した場合、 通電によるコィルからの発熱によリ 容易にモータ温度が 60〜80°Cまで上昇し、 また車載用では周囲温度も加 わって百数十度 °Cまで達するために、 温度上昇による磁気特性の低下の影響 を少なくするには、 室温での保磁力を極力大きくすることが産業応用上不可 欠な課題となっている。  [0005] Fig. 1 shows the temperature dependence of the remanent magnetization (B r) and coercive force (H c j) of a typical N d_F e_B magnet. From Fig. 1, it can be seen that N d_F e_B magnets have the essential problem that the magnetic properties greatly decrease with increasing temperature, and in particular, the rate of decrease in coercive force is large. Therefore, when N d _ F e _B system magnets are used for small motors, etc., the motor temperature easily rises to 60 to 80 ° C due to heat generated from the coil when energized. In order to reduce the influence of the decrease in magnetic properties due to temperature rise to reach hundreds of degrees Celsius, increasing the coercive force at room temperature is an essential issue for industrial applications. .
[0006] さらに、 平板や軸などの基材上に成膜した薄膜磁石は、 その厚さ方向に N d 2 F e 14B結晶の C軸を成長させ、 この膜厚方向に着磁をして用いられるこ とが多い。 この場合の薄膜磁石は、 例えば、 薄膜の厚さが数// m〜数十 m 程度であり、 平板の四辺の長さや軸の直径に対して数十分の 1から百分の 1 となり、 膜面に対して垂直方向に着磁する際には、 反磁界が非常に大きくな つてしまう第 1の問題がある。 また、 この薄膜磁石を機器に組み込む場合に は磁石の動作点が小さいために、 保磁力が小さい場合には残留磁化が低下し て充分な磁束が得られにくい第 2の問題がある。 前者の問題は、 磁石形状と 寸法を好適に設計する、 及び鉄ヨーク材とを組み合わせるなど、 反磁界を減 らすような設計手法を用いることが有益となる。 後者の問題は、 磁石材料特 性の向上によって 1. 5 MAZm以上の保磁力を得ることが必須である。 [0006] Furthermore, a thin film magnet formed on a substrate such as a flat plate or a shaft grows the C axis of the N d 2 F e 14 B crystal in the thickness direction, and is magnetized in this film thickness direction. Often used. In this case, for example, the thin film magnet has a thin film thickness of about several tens of meters / m to several tens of meters, and is a few tenths to one hundredth of the length of the four sides of the flat plate and the shaft diameter. When magnetizing in the direction perpendicular to the film surface, there is a first problem that the demagnetizing field becomes very large. In addition, when this thin-film magnet is incorporated into a device, since the operating point of the magnet is small, there is a second problem that when the coercive force is small, the residual magnetization is lowered and it is difficult to obtain a sufficient magnetic flux. For the former problem, it is beneficial to use a design method that reduces the demagnetizing field, such as designing the magnet shape and dimensions appropriately, and combining with iron yoke materials. For the latter problem, it is essential to obtain a coercive force of 1.5 MAZm or more by improving the magnetic material properties.
[0007] したがって、 最大エネルギー積と同様に保磁力を如何に大きくするかが、 薄膜磁石を実用化する上で重要となる。 保磁力増加の一例として、 スパッタ リング法によって N d_F e_B合金を成膜した後に熱処理を行うことによ リ、 所定の条件下で保磁力 H c jがおよそ 1. 3MAZmの薄膜が得られた 例が報告されている （特許文献 2) 。 しかし、 この薄膜の残留磁化 B rは 0 . 31 Tであり、 焼結磁石の 1. 4 Τと比較して極めて低いために実用化は 困難である。 [0007] Therefore, how to increase the coercive force as well as the maximum energy product is important in putting the thin film magnet into practical use. As an example of increasing the coercive force, a thin film with a coercive force H cj of approximately 1.3 MAZm was obtained under a given condition by performing heat treatment after forming an N d_F e_B alloy by sputtering. It has been reported (Patent Document 2). However, the remanent magnetization B r of this thin film is 0 It is difficult to put it into practical use because it is 31 T and is extremely low compared with 1.4 mm of sintered magnets.
[0008] 他方、 前述と同様な手法でシリコン基板上に Mo下地を形成した後に、 N d_F e_B及び Mo保護層を順次形成して、 引き続き熱処理を行った総厚 0. 9 の薄膜で1. 82MAZmの保磁力が得られている （非特許文献 2) 。 しかし、 この薄膜の残留磁化は約 0. 7 Tと低く且つ 1 m以下の膜 厚のため、 超小型モータやセンサ等への応用においては、 これらの機器を動 作させるために必要な量の磁束が得られず実用面で問題がある。  [0008] On the other hand, after forming a Mo base on a silicon substrate by the same method as described above, N d_F e_B and a Mo protective layer were sequentially formed, followed by heat treatment, and a thin film having a total thickness of 0.9 was obtained. A coercive force of 82 MAZm has been obtained (Non-Patent Document 2). However, the remanent magnetization of this thin film is as low as about 0.7 T and the film thickness is 1 m or less. There is a problem in practical use because magnetic flux cannot be obtained.
[0009] 一方、 本発明者等は、 先に、 N d_F e_B系焼結磁石の表面から、 N d2 [0009] On the other hand, the inventors of the present invention, first, from the surface of the N d_F e_B based sintered magnet, N d 2
F e14 B結晶の粒界部に D yや T b金属を拡散浸透させることにより、 残留 磁化の低下を抑制しつつ保磁力を効果的に向上させた （特許文献 3) 。 また 、 N d-F e _ B系薄膜磁石において N d 2 F e 4 B結晶粒を単磁区粒径以上 に大きくし、 合わせて結晶粒界相を形成することにより、 3 |>が0. 8Tで H c jが 1. 5 MAZmの特性をもつ着磁性に優れた薄膜磁石を得ている （ 特許文献 4) 。 Dy and Tb metals were diffused and permeated into the grain boundary part of the Fe 14 B crystal to effectively improve the coercive force while suppressing a decrease in remanent magnetization (Patent Document 3). In N dF e _ B thin film magnets, N d 2 F e 4 B crystal grains are made larger than the single domain grain size, and a grain boundary phase is formed. A thin film magnet with H cj of 1.5 MAZm and excellent magnetism has been obtained (Patent Document 4).
[0010] なお、 薄膜を積層した磁石については、 N d— F e— Bと F eを積層させ た交換スプリング磁石を製作した報告例 （特許文献 5) があるが、 この例で は残留磁化が向上して保磁力が低下し、 また N d 2 F e 4 B結晶粒径が 1 m 未満であるなど、 本発明とは目的と構成物が異なる。 さらに、 N d_F e_ Bと T aを積層させた薄膜磁石の報告例 （非特許文献 3) があるが、 この例 では T aの採用により N d 2 F e 14B結晶の配向性を向上させたものであり、 保磁力を向上させる効果はなくその値は 0. 9 MAZmで小さい。 [0010] There is a report example (Patent Document 5) of producing an exchange spring magnet in which Nd-Fe-B and Fe are laminated for a thin film-laminated magnet. As a result, the coercive force is reduced and the N d 2 F e 4 B crystal grain size is less than 1 m. Furthermore, there is a report example of a thin-film magnet in which N d_F e_ B and Ta are laminated (Non-patent Document 3). In this example, the use of Ta improves the orientation of the N d 2 F e 14 B crystal. Therefore, there is no effect of improving the coercive force, and its value is as small as 0.9 MAZm.
[0011] 特許文献 1 ：特開平 8-83713号公報  Patent Document 1: Japanese Patent Laid-Open No. 8-83713
特許文献 2：特開平 11 -288812号公報  Patent Document 2: Japanese Patent Laid-Open No. 11-288812
特許文献 3：特開 2005-011973号公報  Patent Document 3: JP 2005-011973
特許文献 4： WO 2005/091 31 5 A 1公報  Patent Document 4: WO 2005/091 31 5 A 1 Publication
特許文献 5：特開平 11 -214219号公報  Patent Document 5: Japanese Patent Laid-Open No. 11-214219
非特許文献 1 ： 日本応用磁気学会誌、 27巻、 1 0号、 1 007頁、 2003 年 Non-Patent Document 1: Journal of Japan Society of Applied Magnetics, 27, 10, 1 007, 2003 Year
非特許文献 2： Journal of Appl ied Physics. 98巻、 1 1 3905頁、 20 05年  Non-Patent Document 2: Journal of Applied Physics. Vol. 98, 1 1 3905, 20 05
非特許文献 3：電気学会研究会資料、 MAG— 03— 1 50、 2003年 発明の開示  Non-Patent Document 3: IEICE Technical Committee Materials, MAG-03-03, 2003, Invention Disclosure
発明が解決しょうとする課題  Problems to be solved by the invention
[0012] N d2F e 14B化合物は高い飽和磁化と高い結晶磁気異方性をもつことから 、 焼結磁石や薄膜磁石の形態において高い残留磁化と比較的大きな保磁力が 得られている。 薄膜磁石は、 一般的に単磁区粒子径に相当するおよそ 0. 3 U m以下の N d 2 F e 14B結晶粒から成る。 この薄膜磁石の保磁力を向上させ るには、 例えば、 本発明者等が先に開発したように （特許文献 4) 、 原料合 金に N dよリ大きな磁気異方性を示す D y等を添加して N dと共に成膜させ る方法があるが、 この方法では （N d， Dy) 2 F e 14 B結晶が生成して保磁 力が向上するものの、 結晶内での D yと F eの磁気的な結合が反平行となる ために磁気モーメン卜が著しく低下して、 残留磁化が大きく低下する問題が あった。 [0012] Since N d 2 F e 14 B compounds have high saturation magnetization and high magnetocrystalline anisotropy, high remanence and relatively large coercive force have been obtained in the form of sintered magnets and thin film magnets. . Thin-film magnets are generally composed of N d 2 Fe 14 B crystal grains of approximately 0.3 U m or less, which corresponds to a single domain particle diameter. In order to improve the coercive force of this thin film magnet, for example, as previously developed by the present inventors (Patent Document 4), the raw material alloy has a magnetic anisotropy greater than Nd, such as Dy. There is a method of forming a film with Nd by adding Nd, but in this method, although (Nd, Dy) 2 F e 14 B crystal is generated and the coercive force is improved, Dy and D Since the magnetic coupling of Fe is antiparallel, there is a problem that the magnetic momentum is significantly lowered and the remanent magnetization is greatly lowered.
課題を解決するための手段  Means for solving the problem
[0013] 本発明者等は、 N d_F e_B系薄膜磁石の保磁力を向上することを目的 として、 成分組成と結晶組織の研究を鋭意重ねた結果、 N d_F e_B系合 金膜と M又は M合金 （ただし、 Mは、 P r， Dy， T b, H oの一種又は二 種以上） 膜を積層させた後に熱処理することによって、 M元素が N dと一部 置換して固溶した （N d、 M) 2F e14B結晶が表面部に形成された N d2F e i4B¾i口曰ョ と、 N d2「 e i4 B結晶粒の粒界に （N d、 M) 2 e 14 B条ロ 晶と界面を接して形成された M元素を主とする結晶粒界相 （又は単に 「粒界 相」 という） とから成る薄膜磁石において、 残留磁化の低下が極めて小さく 且つ保磁力を大幅に向上させ、 残留磁化が 1. 26 T以上、 保磁力 1 060 kAZm以上の薄膜磁石を提供することに成功したものである。 [0013] As a result of intensive research on the component composition and crystal structure for the purpose of improving the coercive force of the N d_F e_B thin film magnet, the present inventors have determined that the N d_F e_B alloy film and M or M Alloy (However, M is one or more of Pr, Dy, Tb, and Ho) After stacking the films, heat treatment is performed, so that M element partially replaces Nd and becomes solid solution ( N d, M) 2 F e 14 B crystals formed on the surface, N d 2 F ei 4 B¾i 口 曰 and N d 2 “ei 4 B crystal grain boundaries (N d, M) 2 In a thin-film magnet composed of a grain boundary phase (or simply called “grain boundary phase”) composed mainly of M element formed in contact with the interface between the e 14 B strand and the B crystal, the decrease in residual magnetization is extremely small and maintained. It has succeeded in providing a thin-film magnet with a remanent magnetization of 1.26 T or more and a coercive force of 1 060 kAZm or more, with greatly improved magnetic force.
[0014] すなわち、 本発明は、 下記のとおりである。 (1 ) M又は M合金 （ただし、 Mは、 P r， Dy， T b, H oの一種又は二 種以上） 膜と N d _ F e _B系合金膜とが交互に積層された 3層以上の積層 構造を熱処理して M又は M合金成分と N d— F e— B系合金成分を相互拡散 させてなる薄膜希土類磁石であって、 [0014] That is, the present invention is as follows. (1) M or M alloy (where M is one or more of Pr, Dy, Tb, and Ho) Three layers in which films and Nd_Fe_B alloy films are alternately stacked A thin-film rare earth magnet obtained by heat-treating the above laminated structure and interdiffusing the M or M alloy component and the Nd-Fe-B alloy component,
該熱処理によリ N d 2 F e 4 B結晶粒の表面部に M元素が N dと置換して固溶 された （N d、 M) 2 F e 14B結晶が形成され、 かつ N d 2 F e 14B結晶粒の 粒界に （N d、 M) 2 F e 14B結晶と界面を接して M又は M合金からなる結晶 粒界相が形成されてなることを特徴とする薄膜希土類磁石。 The heat element M by the surface portion of the Li N d 2 F e 4 B crystal grains process is dissolved by replacing the N d (N d, M) 2 F e 14 B crystals are formed, and N d A thin film rare earth characterized in that a crystal grain boundary phase made of M or M alloy is formed at the interface of (N d, M) 2 F e 14 B crystal at the grain boundary of 2 F e 14 B crystal grain magnet.
[0015] (2) 薄膜の厚さ方向に N d2F e14B結晶相が層状に形成され、 該結晶相の 層間に （N d、 M) 2 F e 14B結晶と界面を接して M又は M合金からなる結晶 粒界相が形成されてなることを特徴とする上記 （1 ) の薄膜希土類磁石。 [0015] (2) An N d 2 F e 14 B crystal phase is formed in layers in the thickness direction of the thin film, and the (N d, M) 2 F e 14 B crystal is in contact with the interface between the crystal phases. The thin film rare earth magnet according to (1) above, wherein a crystal grain boundary phase made of M or an M alloy is formed.
(3) 薄膜の厚さ方向に N d 2 F e 14B結晶相が層状に形成され、 N d2F e i 4 B結曰ヨ の周囲に (N d、 2 F" e 14 B結晶と界面を接して N d 2 F" e 14 B結晶粒を取り囲む M又は M合金からなる結晶粒界相が形成されてなること を特徴とする上記 （1 ) の薄膜希土類磁石。 (3) N d 2 F e 14 B crystal phase is formed in layers in the thickness direction of the film, around the N d 2 F ei 4 B Yui曰Yo (N d, 2 F "e 14 B crystal and an interface A thin film rare earth magnet as described in (1) above, wherein a grain boundary phase made of M or an M alloy surrounding N d 2 F "e 14 B crystal grains is formed.
(4) N d 2 F e 14B結晶粒の平均結晶粒径が 0. 5 m〜 30 mであるこ とを特徴とする上記 （1 ) の薄膜希土類磁石。 (4) The thin-film rare earth magnet according to (1) above, wherein the average grain size of the N d 2 F e 14 B crystal grains is 0.5 m to 30 m.
[0016] (5) N d_F e_B系合金が N d2F e14B化合物からなり、 薄膜中の M元 素の含有量が 1〜 30質量％であり、 且つ N dと M元素の合計含有量が 28 〜45質量％であることを特徴とする上記 （1 ) の薄膜希土類磁石。 [0016] (5) The N d_F e_B alloy is composed of an N d 2 F e 14 B compound, the content of M element in the thin film is 1 to 30% by mass, and the total content of N d and M element The thin film rare earth magnet as set forth in (1) above, wherein the amount is 28 to 45% by mass.
[0017] (6) N d 2 F e 14B化合物の F eの 30質量％未満が C o， N i， T i， V ， C r , C u, A I , Z n， G a, V， Mo, N b, T a, Wの一種又は 2 種以上の元素で置換されていることを特徴とする上記 （6) の薄膜希土類磁 石。 [0017] (6) Less than 30% by mass of Fe of N d 2 Fe 14 B compound is Co, Ni, Ti, V, Cr, Cu, AI, Zn, Ga, V, The thin-film rare earth magnet according to (6) above, which is substituted with one or more elements of Mo, Nb, Ta, and W.
[0018] (7) 薄膜構成原料や成膜と熱処理工程から由来する不可避不純物を含むこ とを特徴とする上記 （1 ) の薄膜希土類磁石。  [0018] (7) The thin film rare earth magnet according to (1) above, which contains inevitable impurities derived from a thin film constituting raw material and film formation and heat treatment steps.
[0019] (8) 薄膜の厚さが 1 m〜300 mであることを特徴とする上記 （1 ) の 薄膜希土類磁石。 (9) 残留磁化 B rが 1. 26 T以上であることを特徴とする上記 （1 ) の 薄膜希土類磁石。 [0019] (8) The thin film rare earth magnet of (1) above, wherein the thickness of the thin film is 1 m to 300 m. (9) The thin film rare earth magnet according to (1) above, wherein the residual magnetization B r is 1.26 T or more.
(1 0) 保磁力 H c jが 1 060 kAZm以上であることを特徴とする上記 (1 ) の薄膜希土類磁石。  (1 0) The thin-film rare earth magnet according to (1) above, wherein the coercive force H c j is 1 060 kAZm or more.
[0020] (1 1 ) 減圧容器内で物理的成膜法により、 N d_F e_B系合金と M金属 又はその合金 （ただし、 Mは、 P r， Dy， T b, H oの一種又は二種以上 ) を交互に積層して成膜し、 その後に 700〜1 1 00°Cの熱処理を行うこ とによリ M又は M合金成分と N d _ F e _ B系合金成分を相互拡散させて、 該 N d 2 F e 14B結晶粒の表面部に M元素が N dと置換して固溶された （N d 、 M) 2 F e 14B結晶を形成し、 かつ N d 2 F e 14B結晶の粒界に （N d、 M ) 2 F e 14B結晶と界面を接して M又は M合金からなる結晶粒界相を形成する ことを特徴とする上記 （1 ) の薄膜希土類磁石の製造方法。 [0020] (1 1) N d_F e_B alloy and M metal or alloys thereof by physical film-forming method in a vacuum container (where M is one or two of Pr, Dy, Tb, Ho) Are alternately laminated, and then heat-treated at 700 to 1100 ° C to mutually diffuse the M or M alloy component and the N d _Fe _ B alloy component. The element M is substituted with N d to form a solid solution (N d, M) 2 F e 14 B crystal on the surface of the N d 2 F e 14 B crystal grains, and N d 2 F The thin film rare earth according to (1) above, wherein a grain boundary phase composed of M or an M alloy is formed at the grain boundary of e 14 B crystal in contact with the (N d, M) 2 F e 14 B crystal interface. Magnet manufacturing method.
(1 2) 最初に 400〜650°Cで N d _ F e— B系膜中に N d 2 F e 14B化 合物の結晶生成を行い、 その後に 700〜1 1 00°Cで熱処理する 2段階の 熱処理を行うことを特徴とする上記 （1 1 ) の薄膜希土類磁石の製造方法。 (1 2) First crystal formation of N d 2 F e 14 B compound in N d _ F e-B film at 400-650 ° C, followed by heat treatment at 700-1100 ° C The method for producing a thin-film rare earth magnet according to (1 1) above, wherein two-stage heat treatment is performed.
(1 3) N d _ F e— B系合金膜の一層の膜厚を 0. 05 m〜50 mと し、 N d _ F e _B系合金と M金属又はその合金の膜厚比を 99 ： 1〜60 (1 3) The thickness of one layer of N d _ F e-B alloy film is 0.05 m to 50 m, and the film thickness ratio of N d _ F e _B alloy and M metal or its alloy is 99 : 1-60
： 40として成膜することを特徴とする上記 （1 1 ) 又は （1 2) の薄膜希 土類磁石の製造方法。 The method for producing a thin-film rare earth magnet according to (1 1) or (1 2), wherein the film is formed as 40.
[0021] 本発明では、 例として、 N d_F e_B系膜と Dyなどの M金属又はその 合金 （以下 M合金という） 膜を交互に積層成膜して M金属又は M合金を N d -F e _ B系膜に熱拡散させることにより、 M元素の一部は形成された N d 2 F e 4B結晶粒に N dと置換して固溶するが、 残部の多くは該結晶粒の周囲 又は Z及び N d2F e14B結晶相の層間に粒界相を形成する。 また、 N d_F e_B系膜の拡散し易い N dの一部は M金属又は M合金膜に拡散する。 [0021] In the present invention, as an example, an N d_F e_B film and an M metal such as Dy or an alloy thereof (hereinafter referred to as an M alloy) are alternately stacked to form an M metal or an M alloy as N d -F e. by thermal diffusion to _ B based film, around part of a solid solution by substituting the N d to N d 2 F e 4 B crystal grains formed, many of the remainder the crystal grains of the element M Alternatively, a grain boundary phase is formed between the Z and N d 2 F e 14 B crystal phases. In addition, a part of N d that easily diffuses in the N d_F e_B film diffuses into the M metal or M alloy film.
[0022] この結晶組織構造によリ、 残留磁化の低下の要因となる N d 2 F e 4 B結晶 粒への M元素の過度の固溶を制限する結果、 残留磁化の低下を抑制しつつ保 磁力の大幅な向上を果たすことが可能となる。 例えば、 ^と1\1金属が50 : 50 で固溶 （置換） すると残留磁化が 30%程度低下するため、 N d2F e14B結晶 の Ndに対する M金属固溶比率を 20〜30%程度とし、 保磁力を向上しながら残 留磁化の低下を 5〜10%以下とするのが、 保磁力と残留磁化がともに高い磁気 特性を得るのに好適である。 [0022] With this crystal structure, as a result of restricting excessive solid solution of M element in the N d 2 F e 4 B crystal grains, which is a cause of a decrease in remanent magnetization, it is possible to suppress a decrease in remanent magnetization. The coercive force can be greatly improved. For example, ^ and 1 \ 1 metal are 50:50 In order to solid solution (substituted) Then the residual magnetization is decreased about 30%, the M metal solid solution ratio of Nd of N d 2 F e 14 B crystal is about 20-30%, residual magnetization while improving the coercive force It is preferable to obtain a magnetic property with a high coercive force and remanent magnetization of 5 to 10% or less.
また、 この結晶組織構造の形成には、 薄膜磁石が基板に対して垂直に高度 に配向した状態での結晶化と配向性の向上及び M元素の拡散を生じるような 600±50°Cと 700〜 1100°Cの中、 より好ましくは 900〜 1100°Cの高温領域 での二段熱処理が望ましく、 従来の N d2F e14Bの単磁区結晶粒径 （0.3 m) より大きな、 0. 5 m〜30 m、 より好適には 1 m〜 5 m位の N d2F e14 B結晶粒が熱処理によリ生成されて、 焼結磁石と似通った磁化機 構をもつようになリ、 薄膜磁石を機器に装着する上で重要な着磁性も向上す る効果がある。 In addition, the formation of this crystallographic structure involves 600 ± 50 ° C and 700 ° C, which causes crystallization and improved orientation and diffusion of M element in a state where the thin film magnet is highly oriented perpendicular to the substrate. It is desirable to perform two-stage heat treatment in the high temperature region of ~ 1100 ° C, more preferably 900 ~ 1100 ° C, which is larger than the conventional single domain grain size (0.3 m) of N d 2 F e 14 B. N d 2 Fe 14 B crystal grains of about 5 m to 30 m, more preferably about 1 m to 5 m are formed by heat treatment to have a magnetization mechanism similar to that of a sintered magnet. It has the effect of improving magnetism, which is important for attaching thin film magnets to equipment.
発明の効果  The invention's effect
[0023] 本発明により、 薄膜磁石の残留磁化の低下を抑制しつつ保磁力を大幅に増 加させた薄膜希土類磁石を提供することができる。  [0023] According to the present invention, it is possible to provide a thin-film rare earth magnet having a significantly increased coercive force while suppressing a decrease in residual magnetization of the thin-film magnet.
図面の簡単な説明  Brief Description of Drawings
[0024] [図 1] N d-F e _ B系磁石の磁気特性と温度の関係図である。 [0024] FIG. 1 is a diagram showing the relationship between the magnetic properties and temperature of an N d-F e _B magnet.
[図 2]本発明の薄膜希土類磁石の結晶相、 結晶粒、 結晶粒界相の構造を示す模 式図である。 （a) 見取り図、 （b) 膜厚方向の A断面図、 （c) B平面図  FIG. 2 is a schematic diagram showing the structure of the crystal phase, crystal grains, and grain boundary phase of the thin film rare earth magnet of the present invention. (A) Floor plan, (b) A cross section in the film thickness direction, (c) B plan view
[図 3]本発明試料 （6) の図面代用 S EM画像である。 [Fig. 3] Drawing SEM image of the sample (6) of the present invention.
[図 4]本発明試料 （3) と比較例試料 （1 ) の X線回折パターンである。  [Fig. 4] X-ray diffraction patterns of the sample of the present invention (3) and the comparative sample (1).
[図 5]本発明試料 （1 0) 〜 （1 4) と比較例試料 （7) 〜 （9) の、 Dy_ [Fig. 5] Dy_ of the samples of the present invention (10) to (14) and the comparative samples (7) to (9)
C o膜厚に対する磁気特性の関係図である。 It is a relationship figure of the magnetic characteristic with respect to Co film thickness.
[図 6]本発明試料 （24) 〜 （30) と比較例試料 （1 2) 〜 （1 3) の、 膜 厚に対する磁気特性の関係図である。  FIG. 6 is a relationship diagram of magnetic characteristics with respect to film thickness of the samples (24) to (30) of the present invention and the samples of comparative examples (12) to (13).
符号の説明  Explanation of symbols
[0025] 1 N d 2 M又は M合金結晶粒界相 [0025] 1 N d 2 M or M alloy grain boundary phase
3 (N d , M) 2 "~ β 1 4 ϋ¾3曰 S  3 (N d, M) 2 "~ β 1 4 ϋ¾3 曰 S
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0026] (合金系■結晶組織構造の説明）  [0026] (alloy system ■ explanation of crystal structure)
本発明で対象とする薄膜磁石は、 N d_F e_B系合金から成り、 一般的 には、 N d， F e, Bを必須成分元素とした N d 2 F e 14B結晶相を主たる構 成物とする。 合金製作に用いる N dは、 Ceや P rなど他の希土類元素を不 純物として、 あるいは原料コス卜低減のために 5質量％程度まで含有して構 わない。 また、 薄膜構成原料や成膜と熱処理工程から由来する不可避不純物 を含む。 The thin-film magnet targeted by the present invention is made of an N d_F e_B alloy, and generally consists mainly of an N d 2 Fe 14 B crystal phase containing N d, F e, and B as essential component elements. And Nd used for alloy production may contain other rare earth elements such as Ce and Pr as impurities or up to about 5% by mass to reduce raw material cost. It also contains inevitable impurities derived from thin film constituent materials and film formation and heat treatment processes.
[0027] また、 薄膜磁石の N d2F e14B結晶粒を微細化するためやキュリー温度向 上などのために、 F e成分の一部を Co, N i， T i， V， C r , C u, A I， Z n， G a, V， Mo, N b, T a, Wの一種又は 2種以上の元素で置 換することが行われる。 F eに対する置換量は各元素によって異なるが、 例 えば、 C uや M oは 1質量％程度の置換量で結晶粒の大きさの均一化と微細 化に効果があリ、 C oは 20質量％の置換量でキュリ一温度が 1 00°C程度 向上する効果がある。 [0027] In addition, the N d 2 F e 14 B crystal grains of the thin film magnet, such as for or Curie temperature toward the upper to miniaturization, a portion of the F e components Co, N i, T i, V, C Replacement with one or more elements of r, Cu, AI, Zn, Ga, V, Mo, Nb, Ta, W is performed. The amount of substitution for Fe varies depending on each element. For example, Cu and Mo are effective for uniformizing and refining the grain size with a substitution amount of about 1% by mass. The effect of improving the Curie temperature by about 100 ° C with a mass% substitution amount.
[0028] しかし、 これらの元素の置換量が 30質量％以上になると F e原子が有す る本来の磁気モーメン卜を薄めることになリ、 磁石の残留磁化と最大エネル ギ一積の大幅な低下を招くためにその置換量は 30質量％未満とする必要が ある。 さらに、 N d_F e_B系希土類合金は原料精製や成膜及び熱処理に おいて、 酸素や炭素などの不純物の混入を避けがたいが、 磁石特性の確保上 それら不純物を各工程で極力低減することは有益である。  [0028] However, if the substitution amount of these elements is 30% by mass or more, the original magnetic momentum of Fe atoms will be diminished, and the remanent magnetization of the magnet and the maximum energy volume will be greatly reduced. In order to cause a decrease, the amount of substitution must be less than 30% by mass. In addition, N d_F e_B rare earth alloys cannot avoid the incorporation of impurities such as oxygen and carbon during raw material refining, film formation, and heat treatment. It is beneficial.
[0029] 一方、 N d2F e14B結晶相と積層させる M又は M合金結晶相における M元 素は、 P r， Dy， T b, H oの一種又は二種以上であることが保磁力向上 において必要である。 その理由は、 Rを希土類元素とした場合の R2 F e 14B 化合物の結晶磁気異方性が、 Rを P r， Dy， T b, H oとした時に、 Rが N dの場合より数十％から 3倍程度大きいために、 保磁力を向上させるには N d a F e 14Bの N dの一部を上記 M元素で置換して固溶させることが極めて 有効であり、 且つ N d 2 F e 4 B結晶膜の層間に M元素成分を配置することも 有効なためである。 これらの M元素は、 単体の M金属や M合金、 すなわち、 各種成膜法を用いて得ることができる P r， Dy， T b, H oの 2種以上を 混合した合金、 及び M金属と F eや Coなど他の元素との合金であって、 M 元素を 1 0重量％程度以上、 好ましくは 50重量％程度以上含有する合金を 、 磁気特性や耐食性を考慮して用いることができる。 [0029] On the other hand, the M element in the M or M alloy crystal phase laminated with the N d 2 F e 14 B crystal phase is guaranteed to be one or more of Pr, Dy, Tb, and Ho. Necessary for improving magnetic force. The reason is that the magnetocrystalline anisotropy of the R 2 F e 14 B compound when R is a rare earth element is greater than when R is N d when R is Pr, Dy, T b, and Ho. To improve the coercive force because it is several tens to three times larger It is very effective to replace a part of N d of N da F e 14 B with the above M element and make it solid solution, and to arrange M element component between the layers of N d 2 F e 4 B crystal film Is also effective. These M elements are a single M metal and M alloy, that is, alloys obtained by mixing two or more of Pr, Dy, Tb, and Ho that can be obtained by using various film forming methods, and M metal and An alloy with other elements such as Fe and Co, and containing an M element of about 10% by weight or more, preferably about 50% by weight or more, can be used in consideration of magnetic properties and corrosion resistance.
[0030] 本発明で対象とする薄膜の基本構成は、 薄膜の厚さ方向に N d 2 F e 14B結 晶相と M又は M合金結晶相が交互に積層した構造を有し、 前者が 1層で後者 がその表裏に各 1層、 又は後者が 1層で前者がその表裏に各 1層の少なくと も計 3層の構成とすることが必須であり、 その積層数は数層から数百層とし ても差し支えない。 [0030] The basic structure of the thin film targeted in the present invention has a structure in which N d 2 Fe 14 B crystal phases and M or M alloy crystal phases are alternately laminated in the thickness direction of the thin film. It is essential that each layer has one layer on the front and back, or one layer on the front and back, and the former has at least three layers each on the front and back. Even hundreds of layers are acceptable.
[0031] 図 2に、 薄膜構成の代表例を模式図で示す。 図 2 (a) は薄膜の見取り図 、 (b) は薄膜の厚さ方向の A断面図、 （c) は B面下の N d 2 F e 14B結晶 相部分の平面図である。 この例は、 例えば、 厚さ 1 m〜2 mの N d _ F 6_8膜と厚さ0. 1 m〜0. 2 の1\1膜を積層して総膜厚が50 の薄膜を熱処理したような場合の模式図である。 この場合、 結晶粒は膜の厚 さ方向には 1層 1個程度になるが、 N d_F e_B膜の厚さを例えば、 1 0 mとすると厚さ方向に数個の N d2 F e 14B結晶が並ぶことになリ、 この場 合には保磁力や c軸配向性がやや低下する。 N d_B_F e系膜と M金属又 は M合金膜を交互に成膜したままでは各膜はアモルファス又は 1 fjl m以下の 微細結晶からなるが、 熱処理後は、 図 2 (b) 、 図 2 (c) に示すように、 N d2F e14 B結晶粒 1を M金属又は M合金からなる結晶粒界相 2が取リ囲み 、 且つ N d 2 F e 14B結晶粒 1の表面部は M金属又は M合金の M成分が N dと 相互置換して部分的に固溶した （N d， M) 2F e14B結晶 3となっている。 図 2 (c) は、 N d2F e14B結晶粒 1がほぼランダムに配置された構造を示 している。 FIG. 2 is a schematic diagram showing a typical example of a thin film configuration. 2 (a) is a thin film of perspective, (b) the thickness direction of the A cross-sectional view of a thin film, (c) is a plan view of the N d 2 F e 14 B crystal phase portion of the lower surface B. In this example, for example, an Nd_F6_8 film with a thickness of 1 m to 2 m and a 1 \ 1 film with a thickness of 0.1 m to 0.2 were laminated and a thin film with a total thickness of 50 was heat-treated. It is a schematic diagram in such a case. In this case, the number of crystal grains is about one per layer in the thickness direction of the film, but if the thickness of the N d_F e_B film is 10 m, for example, several N d 2 F e 14 in the thickness direction In this case, the coercive force and c-axis orientation are slightly reduced. If the N d_B_F e system film and M metal or M alloy film are alternately formed, each film consists of amorphous or fine crystals of 1 fjl m or less, but after heat treatment, it is shown in Fig. 2 (b) and Fig. 2 ( c) As shown in Fig. 1, N d 2 F e 14 B crystal grain 1 is surrounded by a grain boundary phase 2 made of M metal or M alloy, and the surface portion of N d 2 F e 14 B crystal grain 1 is The M component of the M metal or M alloy is (Nd, M) 2 Fe 14 B crystal 3 in which the M component is mutually substituted and partially dissolved. Figure 2 (c) shows a structure in which N d 2 F e 14 B crystal grains 1 are arranged almost randomly.
[0032] 図 2 (b) の下図、 及び上図は、 それぞれ N d2F e14B結晶粒 1が積み重 なった構造を示しており、 薄膜構成は、 下層から上方に向かって M金属又は M合金からなる結晶粒界相 2、 N d 2 F e 14B結晶粒 1、 M金属又は M合金か らなる結晶粒界相 2、 N d 2 F e 14B結晶粒 1、 M金属又は M合金からなる結 晶粒界相 2の 5層構成となっている。 なお、 図 2 (b) の下図は、 M金属又 は M合金膜が比較的薄く、 総膜厚に対する N d2F e14B及び（N d,M)2F e i 4 Bの量比が大きい場合であり、 N d 2 F e 14B結晶相の層間に M又は M合金 からなる結晶粒界相 2が配置した構造を示しておリ、 総膜厚に対する N d 2 F e 4 B及び（N d , M) 2 F e 4 Bの量比が大きいほど残留磁化は高くなる。 図 2 (b) の上図は、 N d2F e14B結晶粒1の周囲及び該結晶相の層間にM又は M合金からなる結晶粒界相 2が配置した構造を示しておリ、 これは M金属又 は M合金膜が比較的厚い場合であり、 N d 2 F e 14B結晶粒を結晶粒界相 2及 び （N d， M) 2 F e 14B結晶 3が完全に包囲しているため保磁力は、 下図の 場合よりも大きくなる。 [0032] The lower and upper diagrams in Fig. 2 (b) show the stacking of N d 2 F e 14 B crystal grains 1 respectively. The structure of the thin film consists of a grain boundary phase 2 made of M metal or M alloy upward from the lower layer, N d 2 F e 14 B crystal grain 1, M metal or M alloy. It has a five-layer structure consisting of grain boundary phase 2, N d 2 Fe 14 B crystal grain 1, crystal grain boundary phase 2 made of M metal or M alloy. The lower figure in Fig. 2 (b) shows that the M metal or M alloy film is relatively thin, and the amount ratio of N d 2 F e 14 B and (N d, M) 2 F ei 4 B to the total film thickness is This shows a structure in which the grain boundary phase 2 made of M or M alloy is arranged between the layers of the N d 2 F e 14 B crystal phase, and N d 2 F e 4 B and the total film thickness The larger the quantity ratio of (N d, M) 2 F e 4 B, the higher the remanent magnetization. The upper diagram of FIG. 2 (b) shows a structure in which a grain boundary phase 2 made of M or an M alloy is arranged around the N d 2 F e 14 B crystal grain 1 and between the crystal phases. This is the case when the M metal or M alloy film is relatively thick, and the N d 2 F e 14 B crystal grains are completely separated from the grain boundary phase 2 and (N d, M) 2 F e 14 B crystal 3. Since it is surrounded, the coercive force is larger than in the case of the figure below.
[0033] 薄膜中の N dと M元素の含有量に関しては、 N d2F e14B化合物の理論的 な N d含有量が 26. 7質量％に相当するため、 本発明の構成では、 M金属 又は M合金からなる粒界相を生成させるために、 N dと M元素の含有量の下 限は 26. 7質量％に加えて少なくとも 0. 3質量％程度多い、 すなわち、 約 27質量％以上であることが必要であり、 それ未満では M金属又は M合金 からなる粒界相が相対的に極めて薄くなるか、 又は薄膜中に Of- F eが析出す るなどにより、 本発明の保磁力向上効果を得ることが実質的に困難となる。 [0033] With respect to the content of N d and M elements in the thin film, since the theoretical N d The content of N d 2 F e 14 B compound corresponds to 26.7 wt%, in the configuration of the present invention, In order to generate a grain boundary phase composed of M metal or M alloy, the lower limit of the content of Nd and M elements is 26.7% by mass and at least 0.3% by mass, that is, about 27% by mass. % Or less, and below that, the grain boundary phase composed of M metal or M alloy becomes relatively very thin, or Of-Fe precipitates in the thin film. It becomes substantially difficult to obtain a coercive force improving effect.
[0034] N d_F e_B系膜内における N d量を 27質量％以上とすることにより 少量の N dリツチ粒界相が N d2F e14 B結晶粒の周囲に形成されるか、 又は M金属又は M合金からなる結晶粒界相内に少量の N dが共存することになる [0034] N d_F e_B system or a small amount of N d Ritsuchi grain boundary phase by the N d amount of 27 mass% or more in the film is formed around the N d 2 F e 14 B crystal grains, or M A small amount of Nd coexists in the grain boundary phase made of metal or M alloy.
[0035] N d-F e _ B系膜に対する M金属又は M合金膜の膜厚を相対的に高める ことにより、 N dと M元素の含有量が多くなリ、 その効果として保磁力を増 加させることが容易になる。 しかし、 薄膜全体における N dと M元素の含有 量が 45質量％を超えると、 保磁力の増加率が小さくなると共に残留磁化の 低下が著しくなリ、 実用面で利用できる磁束も低下することから、 それらの 合計含有量は 45質量％以下とすることが必要であり、 より好ましくは 40 質量％以下が良い。 [0035] By increasing the film thickness of the M metal or M alloy film relative to the N dF e _ B film, the contents of N d and M elements are increased, and as a result, the coercive force is increased. It becomes easy. However, if the content of Nd and M elements in the whole thin film exceeds 45% by mass, the rate of increase in coercive force decreases and the residual magnetization increases. Since the magnetic flux that can be used in practical use also decreases, the total content thereof needs to be 45% by mass or less, and more preferably 40% by mass or less.
[0036] 薄膜中の M元素の含有量については、 1質量％未満では保磁力の向上率が 数％に留まり、 本発明の効果がきわめて小さい。 一方、 N d_F e_B系膜 に対する M金属又は M合金膜の膜厚を相対的に高めて薄膜全体に占める M元 素含有量を多くするに従って、 保磁力が大幅に向上する。 しかし、 30質量 %を超えると N d元素との合計含有量が 450/0を超えるようになり、 上述同 様に残留磁化が大きく低下するために、 薄膜全体に占める M元素の含有量は 1〜30質量％とすることが必要である。  [0036] When the content of the M element in the thin film is less than 1% by mass, the improvement rate of the coercive force is only a few percent, and the effect of the present invention is extremely small. On the other hand, the coercive force is greatly improved as the M element content in the entire thin film is increased by increasing the film thickness of the M metal or M alloy film relative to the N d_F e_B film. However, if it exceeds 30% by mass, the total content of Nd element exceeds 450/0, and the residual magnetization is greatly reduced as described above, so the content of M element in the entire thin film is 1 It is necessary to make it -30 mass%.
[0037] 薄膜中の M元素含有量を把握するため、 以下に具体例を記載する。 27% N d-F e _ B合金の膜厚が 99に対して D y金属の膜厚を 1とした場合、 膜中の N dは 26. 3質量％で D yは 1質量％となり、 このときの合計含有 量は 27. 3質量0 /oである。 また、 27%N d _ F e— B合金の膜厚が 80 に対して D y金属の膜厚を 20とした場合、 膜中の N dは 20. 1質量％で Dyは 23. 4質量％となり、 このときの合計含有量は 43. 5質量％とな る。 [0037] In order to grasp the M element content in the thin film, a specific example will be described below. When the film thickness of 27% N dF e _ B alloy is 99 and the film thickness of Dy metal is 1, Nd in the film is 26.3 mass% and Dy is 1 mass%. The total content of is 27.3 mass 0 / o. Also, when the film thickness of 27% Nd_Fe-B alloy is 80 and the film thickness of Dy metal is 20, Nd in the film is 20.1% by mass and Dy is 23.4% by mass The total content at this time is 43.5% by mass.
[0038] M元素を一部固溶した N d 2 F e 14B結晶粒の粒径は、 0. 5 m未満では 単磁区粒径に近くなつて着磁性がやや低下すること、 及び熱拡散による結晶 成長をそれ以下に抑えることが技術的に困難となる。 一方、 30 mを超え ると結晶内の磁区が不安定になり、 大きな保磁力が得られなくなる。 したが つて、 その平均結晶粒径は 0. 5 m〜30 mの範囲とすることが必要で あり、 大きな保磁力を得るためには 1 m〜1 0 mとすることがより好まし い。 [0038] When the particle size of N d 2 F e 14 B crystal grains in which M element is partly dissolved is less than 0.5 m, the magnetization decreases slightly as it approaches the single domain particle size, and thermal diffusion It is technically difficult to keep crystal growth below that below. On the other hand, if it exceeds 30 m, the magnetic domain in the crystal becomes unstable, and a large coercive force cannot be obtained. Therefore, the average crystal grain size needs to be in the range of 0.5 m to 30 m, and in order to obtain a large coercive force, it is more preferably 1 m to 10 m.
[0039] 平均結晶粒径の求め方については、 一般に結晶を多方向から輪切リにした 平均寸法から求めるが、 例として、 本発明試料 （6) の T b元素を一部固溶 した N d 2 F e 14B結晶においては、 図 3の薄膜破断面の SEM (走査型電子 顕微鏡） 画像から見るとその結晶粒径はおよそ 2 mと判断される。 しかし ながら、 膜の平面を硝酸アルコールで微弱エッチングした試料を観察すると 、 結晶粒径は 3 m〜 4 mであった。 したがって、 薄膜内の異形な結晶粒 径の正確な測定は困難であるために、 本明細書中では膜断面若しくは膜面内 で観察された結晶の任意な箇所の 50 mX 50 mの範囲内の全結晶粒の 直径の平均寸法を平均結晶粒径と表現している。 [0039] Generally, the average crystal grain size is determined from the average size of the crystal cut from multiple directions. As an example, N in which the Tb element of the sample of the present invention (6) is partially dissolved. The d 2 F e 14 B crystal has a crystal grain size of approximately 2 m when viewed from the SEM (scanning electron microscope) image of the thin-film fracture surface in Fig. 3. However While observing a sample etched weakly with nitric alcohol on the plane of the film, the crystal grain size was 3 m to 4 m. Therefore, since it is difficult to accurately measure the irregular crystal grain size in the thin film, in this specification, it is within the range of 50 m × 50 m at any part of the crystal observed in the film cross section or in the film surface. The average size of the diameters of all crystal grains is expressed as the average crystal grain size.
[0040] (膜厚■成膜法■基材の説明）  [0040] (Film thickness ■ Film formation method ■ Explanation of substrate)
本発明の薄膜希土類磁石の膜の厚さは、 1 m〜300 mの範囲である ときに本発明の効果を充分発揮できる。 未満では、 薄膜の厚さ方向に N d 2 F e 14 B結晶相が層状に形成されるだけであり、 該 N d 2 F e 4 B結晶 粒の周囲又は/及び該結晶相の層間に M又は M合金からなる粒界相が配置した 構造を形成させることが困難であり、 また各種の応用機器においてマシンや センサとして応用するにおいては必要な保磁力が不足する。 The effect of the present invention can be sufficiently exerted when the thickness of the thin film rare earth magnet of the present invention is in the range of 1 m to 300 m. Less than Nd 2 F e 14 B crystal phase is formed only in the thickness direction of the thin film, and M around the N d 2 F e 4 B crystal grain and / or between the crystal phase M Alternatively, it is difficult to form a structure in which grain boundary phases made of M alloy are arranged, and the coercive force required for application as a machine or sensor in various application devices is insufficient.
[0041] 一方、 膜の厚さを大きくすれば保磁力大きくする上で好ましいが、 300 mを超えると薄膜の下部と上部の間で結晶の配向性が悪くなつて残留磁化 が低下する、 及び薄膜面の平滑性が悪くなる、 さらに成膜作業におよそ 1曰 以上の長時間稼働が必要などの問題がある。 なお、 300 m超の厚さは焼 結磁石を切断研磨する方法によっても比較的容易に得られるため、 それを超 える厚さでは薄膜磁石を製作する利点が小さい。 より好ましくは、 1 0 m 〜300 mの範囲、 さらに好ましくは 20 m〜200 mの範囲である  [0041] On the other hand, increasing the thickness of the film is preferable for increasing the coercive force. However, if the thickness exceeds 300 m, the orientation of the crystal deteriorates between the lower and upper portions of the thin film, and the residual magnetization decreases, and There is a problem that the smoothness of the thin film surface is deteriorated, and that the film forming operation needs to be operated for a long time of about 1 mm or more. A thickness of more than 300 m can be obtained relatively easily by cutting and polishing the sintered magnet, so that the thickness exceeding this thickness has a small advantage in producing a thin film magnet. More preferably, it is in the range of 10 m to 300 m, more preferably in the range of 20 m to 200 m.
[0042] 成膜方法については、 減圧容器内で薄膜を構成する元素成分を各種の基材 上に成膜させる、 いわゆる物理的成膜法を用いることができる。 具体的方法 としては、 蒸着、 スパッタリング、 イオンプレーティング、 レーザーデポジ シヨン、 CVD、 及び微細な合金粉末粒子を塗布又は吹きつけるコーティン グなどがある。 これらの物理的成膜法は、 不純物混入が少なく良質の結晶質 膜が得られるため、 N d _ F e _ B系薄膜の成膜法として好適である。 [0042] As a film forming method, a so-called physical film forming method in which an element component constituting a thin film is formed on various base materials in a vacuum container can be used. Specific methods include vapor deposition, sputtering, ion plating, laser deposition, CVD, and coating in which fine alloy powder particles are applied or sprayed. These physical film formation methods are suitable as a film formation method for Nd_Fe_B-based thin films because a high-quality crystalline film can be obtained with few impurities.
[0043] 層状に形成される N d - F e _B系膜の層間に M元素成分として例えば D y金属膜を配置するには、 スパッタリング法を例にとると、 N d_F e_B 合金と Dy金属の各ターゲッ卜を用意し、 基材又はターゲッ卜を移送又は回 転させることによって、 N d_F e_B膜と Dy膜を交互に成膜させて積層 構造をもつ膜を得ることができる。 [0043] To arrange, for example, a Dy metal film as an M element component between layers of a layered Nd-Fe_B-based film, a sputtering method is taken as an example. Nd_Fe_B By preparing each target of alloy and Dy metal and transferring or rotating the base material or target, N d_F e_B film and Dy film can be alternately formed to obtain a film having a laminated structure .
[0044] 各層の膜厚については、 主に磁性を担う N d_F e_B系膜を Dy膜より 厚くさせることが必要であり、 前者の一層の膜厚は 0. 05 m〜50 m 程度、 より好ましくは 0. 3 m〜1 0 m程度とし、 前者と後者の膜厚比 は 99 ： 1〜60 ： 40が良く、 高い残留磁化を維持しつつ高保磁力を得る 上で、 より好ましくは 97 ： 3〜75 ： 25、 さらに好ましくは 95 ： 5〜 85 : 1 5とするのが良い。 各膜の積層形態は、 基材 ZDy/N d_F e_B /Dy、 又は基材 ZN d_F e_B/Dy/N d_F e_Bとし、 積層数をその 数倍〜数百倍に任意に設定することができる。 [0044] Regarding the film thickness of each layer, it is necessary to make the N d_F e_B system film mainly responsible for magnetism thicker than the Dy film, and the thickness of the former layer is more preferably about 0.05 m to 50 m. Is about 0.3 m to 10 m , and the film thickness ratio of the former and the latter is preferably 99: 1 to 60:40, and more preferably 97: 3 for obtaining a high coercive force while maintaining high remanent magnetization. ~ 75: 25, more preferably 95: 5 to 85:15. The lamination form of each film is a base material ZDy / N d_F e_B / Dy or a base material ZN d_F e_B / Dy / N d_F e_B, and the number of laminations can be arbitrarily set to several to several hundred times.
[0045] 薄膜を形成するための基材は、 各種の金属や合金、 ガラス、 シリコン、 セ ラミックスなどを選択して使用することができる。 ただし、 所望の結晶組織 を得るために 600°C以上の高温度での熱処理を行う必要上、 セラミックス や、 金属基材としては F e， Mo, T iなどの比較的高融点の金属を選択す ることが望ましい。  [0045] As the base material for forming the thin film, various metals, alloys, glass, silicon, ceramics and the like can be selected and used. However, in order to obtain the desired crystal structure, it is necessary to perform heat treatment at a high temperature of 600 ° C or higher, and ceramics and metals with relatively high melting points such as Fe, Mo, and Ti are selected as the metal substrate. It is desirable to do this.
[0046] また、 基材が軟磁性を有する場合は薄膜磁石に加わる反磁界が小さくなる 性質を示すことから、 F e， 磁性ステンレス鋼， N iなどの磁性金属や合金 の使用も好適である。 なお、 セラミックス基材を用いると高温処理における 耐性は充分であるが、 N d _ F e _B膜との密着性が不足する場合があり、 その対策として T iや C rなどの下地膜を設けることが有効であることが多 <、 これら下地膜は基材が金属や合金でも有効の場合がある。  [0046] In addition, when the base material has soft magnetism, the demagnetizing field applied to the thin film magnet is reduced, so that the use of magnetic metals and alloys such as Fe, magnetic stainless steel, and Ni is also suitable. . If a ceramic substrate is used, the resistance to high-temperature processing is sufficient, but the adhesion to the Nd_Fe_B film may be insufficient, and as a countermeasure, a base film such as Ti or Cr is provided. In many cases, these base films are effective even when the base material is a metal or an alloy.
[0047] (熱処理の説明）  [0047] (Description of heat treatment)
スパッタリングなどよつて成膜した N d - F e— B系単層膜は、 通常ァモ ルファスもしくは数十 nm程度の微細結晶から成ることが多い。 そのため、 従来は 500〜650°Cの低温熱処理によって結晶化と結晶成長を促進して 平均結晶粒径が 0. 3 m程度の N d 2 F e 14B結晶相を得ている。 本発明で は、 この結晶化に加えて、 N d 2 F e 14B結晶粒内へ M又は M合金膜の M元素 を一部拡散させ、 N dと置換させて固溶させると共に、 M又は M合金から成 る結晶粒界相を N d 2 F e 14 B結晶粒の周囲又は/及び該 N d 2 F e 14 B結曰曰 相の層間に生成させるために、 700〜1 1 00°C、 より好ましくは 700 〜 900°Cの高温熱処理を行うことが必要である。 熱処理は短時間処理が望 ましく、 1分〜 1時間の範囲で充分であり、 M元素の拡散量の制御は時間より も温度変更による方が容易である。 固溶量は、 処理温度が高いほど、 長時間 ほど多くなるが、 相互拡散の関係上 50%位が固溶限界となる。 積層膜相互 の境界面は熱処理によリシャープでなくなリ、 各元素濃度が膜厚方向に傾斜 した組成分布をもつことになるが積層膜の総厚は熱処理後も基本的に変わり ない。 N d -Fe-B single-layer films formed by sputtering or the like are usually composed of amorphous crystals or fine crystals of about several tens of nanometers. Therefore, conventionally, to obtain 500 to 650 ° C low-temperature heat treatment by crystallization and crystal growth by promoting an average grain size of 0.5 about 3 m of N d 2 F e 14 B crystal phase. In the present invention, in addition to this crystallization, the M element of the M or M alloy film enters the N d 2 F e 14 B crystal grains. Is diffused and substituted with N d to form a solid solution, and the grain boundary phase made of M or an M alloy is surrounded by and / or around the N d 2 F e 14 B crystal grains. In order to form between the layers of the B-bonded phase, it is necessary to perform a high-temperature heat treatment at 700 to 110 ° C., more preferably 700 to 900 ° C. A short heat treatment is desirable for the heat treatment, and a range of 1 minute to 1 hour is sufficient, and the control of the diffusion amount of M element is easier by changing the temperature than by the time. The amount of solid solution increases as the processing temperature increases, but the longer the treatment time, the lower the solid solution limit is about 50% due to interdiffusion. The interface between the laminated films is not sharpened by the heat treatment, and the concentration of each element has a composition distribution that is inclined in the film thickness direction, but the total thickness of the laminated film remains basically unchanged after the heat treatment.
[0048] この熱処理においては、 最初に 400〜650°Cで N d _ F e— B系膜中 に N d 2 F e 14B化合物の結晶生成を行い、 その後に 700〜1 1 00°CでN d 2 F e 14 B結晶粒の成長と M又は M合金の N d _ F e _ B系膜への拡散をさ せる、 2段階の熱処理を行っても良い。 特に、 この結晶化のための低温熱処 理では、 磁気異方性の発現に効果的な C軸に沿って配向した結晶粒の形成を 促すために 600±50°Cが望ましい。 なお、 詳しくは M元素が N d 2 F e 14 B結晶粒内に拡散して N d元素の一部と置換すると同時に、 N d成分が M又 は M合金膜の M元素と固溶する相互拡散が積層膜中で進行する。 100°C未 満では、 M元素の拡散に数十時間を要するために実用的でなく、 所望とする 結晶組織を得ることが困難である。 700°C以上になると M元素の N d 2 F e 4 B結晶粒内への拡散と、 N d 2 F e 14B結晶成長と M又は M合金からなる結 晶粒界相の生成が進む。 しかし、 1 1 00°Cを超えると相互拡散により形成 された合金相中の一部の低融点相が融液化しゃすくなって薄膜の平滑性が損 なわれること、 及び薄膜表面の酸化が著しく進行するために、 熱処理温度は 700〜1 1 00°Cとするのが好ましい。 [0048] In this heat treatment, first, crystals of N d 2 F e 14 B compound were formed in the N d _ F e— B-based film at 400 to 650 ° C., and then 700 to 110 ° C. Then, two-stage heat treatment may be performed to grow N d 2 F e 14 B crystal grains and diffuse the M or M alloy into the N d _F e _B film. In particular, in this low-temperature heat treatment for crystallization, 600 ± 50 ° C is desirable in order to promote the formation of crystal grains oriented along the C-axis, which is effective in developing magnetic anisotropy. For details, the M element diffuses into the N d 2 F e 14 B crystal grains and replaces a part of the N d element, and at the same time, the N d component dissolves with the M element of the M or M alloy film. Diffusion proceeds in the laminated film. If it is less than 100 ° C, it takes several tens of hours to diffuse the M element, which is not practical and it is difficult to obtain a desired crystal structure. When the temperature exceeds 700 ° C, diffusion of M element into N d 2 F e 4 B crystal grains, growth of N d 2 F e 14 B crystals, and generation of crystal grain boundary phases consisting of M or M alloys proceed. However, if it exceeds 1100 ° C, some of the low-melting-phase phases in the alloy phase formed by interdiffusion will be melted and the smoothness of the thin film will be impaired, and the oxidation of the thin film surface will be remarkably reduced. In order to proceed, the heat treatment temperature is preferably 700 to 110 ° C.
[0049] 熱処理は、 薄膜表面の酸化を防止するために真空又は非酸化性の雰囲気中 で行うことが必要であり、 加熱方法としては薄膜試料を電気炉へ装填する方 式、 赤外線加熱やレーザー照射によって急速な加熱冷却をする方式、 及び薄 膜に直接通電するジュール加熱方式などを適宜選択して採用することができ る。 [0049] The heat treatment needs to be performed in a vacuum or non-oxidizing atmosphere to prevent oxidation of the thin film surface. As a heating method, a method of loading a thin film sample into an electric furnace, infrared heating or laser Rapid heating and cooling method by irradiation, and thin A Joule heating method for directly energizing the membrane can be appropriately selected and employed.
[0050] また、 スパッタリング法の例では成膜と熱処理を分離して実施した方が薄 膜の結晶性や磁気特性を制御し易いため好ましいが、 スパッタリングの最中 に基材を高温度に加熱しておく方式や、 成膜時の出力を上げることによって 成膜中の温度を 400°C以上、 好ましくは 700°C以上に維持することによ リ、 所望の結晶組織を作りこむことも可能である。 さらに、 N d_F e_B 系膜はさび易いため成膜後又は熱処理後に、 N iや T iなどの耐食性保護膜 を形成して用いるのが通例である。  [0050] Further, in the case of the sputtering method, it is preferable to perform the film formation and the heat treatment separately because it is easy to control the crystallinity and magnetic properties of the thin film, but the substrate is heated to a high temperature during the sputtering. By maintaining the temperature during film formation at 400 ° C or higher, preferably 700 ° C or higher by increasing the output during film formation, the desired crystal structure can be created. It is. Further, since the N d_F e_B film is easily rusted, it is common to form a corrosion-resistant protective film such as Ni or Ti after film formation or after heat treatment.
実施例 1  Example 1
[0051] 以下実施例に従って本発明を詳細に述べる。  [0051] The present invention is described in detail below in accordance with examples.
<スパッタリング法による薄膜磁石の作製、 その 1 >  <Fabrication of thin film magnets by sputtering, part 1>
N d 2 F e 14B化合物の組成に相当する 26. 7%N d - 1. 0%B—残部 F e (単位は質量％) の合金 Aと、 T bを予め含有させた 25%N d _ 1 1 %丁 13_ 1 %3_残部「6 (単位は質量％) の合金 Bをそれぞれ溶解錶造し 、 平面研削を行って径 6 Omm、 厚さ 3 mmの合金 Aと合金 Bの円板状ター ゲットをそれぞれ製作した。 また、 同じ形状と寸法をもつ純度 99. 5%の T b金属ターゲットを同様に製作した。 また、 長さ 8mm、 幅 5mm、 厚さ 0. 3 mmの短冊形状をした純度 99. 9 %の M o板を、 溶剤脱脂と酸洗を して基板とした。 26.7% N d-1. 0% B—the balance F e (unit: mass%) of alloy A corresponding to the composition of N d 2 F e 14 B compound and 25% N containing T b in advance d _ 1 1% Ding 13_ 1% 3_ balance “6 (unit: mass%) of alloy B is melted and cast, and surface grinding is performed to make a 6 mm diameter and 3 mm thick alloy A and alloy B. Each disk-shaped target was manufactured, and a Tb metal target with the same shape and dimensions of 99.5% purity was manufactured in the same way, and it was 8 mm long, 5 mm wide, and 0.3 mm thick. A strip-shaped 99.9% pure Mo plate was subjected to solvent degreasing and pickling to form a substrate.
[0052] 実際の成膜作業は以下の手順で行った。 [0052] The actual film forming operation was performed according to the following procedure.
ぐ比較例試料 1， 2の作製 >  Comparison Samples 1 and 2>
RFスパッタ装置の減圧容器 （チャンバ一） 上部に、 N d_F e_Bの合 金 Aの円板状ターゲッ卜を取り付け、 下部側にはヒータを内蔵させた S US 製平板の上に Mo基板を 2個並べて配置した。 スパッタ装置内を 5 X 1 0-5P aまで真空排気した後、 A rガスを導入して装置内圧力を 1 Paに維持した RF sputtering equipment decompression vessel (chamber one) N d_F e_B alloy A disk target is attached to the upper part, and two Mo substrates are placed on the SUS flat plate with a built-in heater on the lower side. Arranged side by side. After evacuating the inside of the sputtering apparatus to the 5 X 1 0- 5 P a, the reactor was kept in pressure by introducing A r gas to 1 Pa
[0053] 最初に、 Mo基板の逆スパッタを行って表面酸化膜を除去した後、 ヒータ を加熱して S U S製平板面の温度を 400°Cに維持し、 R F出力 20 OWと D C出力 30 OWを加えて厚さ 6 mの N d _ F e _ Bの単層膜を成膜した 。 得られた単層膜をチャンバ一から取り出した。 [0053] First, the Mo substrate is reverse-sputtered to remove the surface oxide film, and then the heater Was heated to maintain the temperature of the SUS flat plate surface at 400 ° C, and an RF output of 20 OW and a DC output of 30 OW were applied to form a 6 m thick N d _ F e _ B single layer film. . The obtained monolayer film was taken out from the chamber.
[0054] ぐ比較例試料 3の作製 >  [0054] Preparation of Gu Comparative Example Sample 3>
次に、 同様に、 Mo基板を 1個配置し N d _ F e_Bの合金 Aの円板状タ ーゲッ卜の代わりに N d _T b_ F e_Bの合金 Bの円板状ターゲッを取り 付けて、 厚さ 6 mの N d _ F e_Bの単層膜を成膜した。 得られた単層膜 をチャンバ一から取り出した。  Next, similarly, place one Mo substrate and attach the disk-shaped target of alloy B of N d _T b_F e_B instead of the disk target of alloy A of N d _F e_B. A single-layer film of Nd_Fe_B having a thickness of 6 m was formed. The obtained monolayer film was taken out from the chamber.
[0055] <比較例試料 4， 5及び本発明試料 （1 ) 〜 （5) の作製 >  [0055] <Production of Comparative Samples 4 and 5 and Samples of the Present Invention (1) to (5)>
さらに、 同様に、 Mo基板を 7個並べて配置し、 N d _ F e_Bの合金 A の円板状ターゲッ卜と T bターゲッ卜を 1 80度対向して取り付け、 各ター ゲットを交互に回転させながら、 順次、 厚さ 0. 2 mの T b、 厚さ 1. 8 tl mの N d - F e _Bを繰り返し成膜し、 T b/N d _ F e_B/T b/N d _ F e_B/T b/N d _ F e_B/T bの積層膜、 総厚 6. 2 mを製作した。 得られた積層膜をチャンバ一から取り出した。  Similarly, seven Mo substrates are arranged side by side, N d _ F e_B alloy A disk target and T b target are mounted facing each other at 180 degrees, and each target is rotated alternately. Then, successively, T b with a thickness of 0.2 m and N d-F e _B with a thickness of 1.8 tl m were repeatedly formed, and T b / N d _ F e_B / T b / N d _ F A multilayer film of e_B / T b / N d _F e_B / T b with a total thickness of 6.2 m was manufactured. The obtained laminated film was taken out from the chamber.
[0056] <熱処理 >  [0056] <Heat treatment>
次に、 上記の方法で得られた単層膜及び積層膜を管状電気炉に装填し、 酸 素濃度を 5 p pm以下に維持した A rガス気流中 1 0分間の熱処理をそれぞ れ行った。 また、 800°Cの熱処理試料 （2) については、 550°C、 600°Cおよび 650°C、 各 30分の低温熱処理を行い、 更に該温度での所定の熱処理 （800°C、 1 0分） を加えた試料 （2' ) . (2' ' ) および （2' ' ' ) も作製した。 成 膜及び熱処理条件と磁気特性を表 1に示す。 本発明試料 （1 ) 〜 （5) につ いては、 それぞれ 700， 800， 900, 1 000， 1 1 00°Cで熱処理 した。 なお、 結晶化のための熱処理は 400°Cから 650°Cで行うことも可能であ るが、 600°Cの方が C軸方向の配高度が向上する点で好ましい。  Next, the monolayer film and the laminated film obtained by the above method were loaded into a tubular electric furnace, and each was heat-treated for 10 minutes in an Ar gas stream maintaining an oxygen concentration of 5 ppm or less. It was. In addition, the heat-treated sample (2) at 800 ° C was subjected to low-temperature heat treatment at 550 ° C, 600 ° C and 650 ° C for 30 minutes each, and a predetermined heat treatment at that temperature (800 ° C, 10 ° C). (2 '). (2' ') and (2' '') were also prepared. Table 1 shows the film formation, heat treatment conditions, and magnetic properties. Samples (1) to (5) of the present invention were heat-treated at 700, 800, 900, 1000, and 1100 ° C, respectively. The heat treatment for crystallization can be performed at 400 ° C. to 650 ° C., but 600 ° C. is preferable from the viewpoint of improving the distribution in the C-axis direction.
[0057] [表 1] [0057] [table 1]
Figure imgf000019_0001
Figure imgf000019_0001
[0058] 各試料の磁気特性は超電導型 VSM (振動試料型磁力計） を用い、 膜面に 垂直方向に ±6 Tの磁界を加えて測定した。 その後に、 各試料の X線回折を 行って N d 2 F e 14B結晶の配向方向、 及び多層膜試料では T b元素の N d 2 F e14B結晶粒への固溶状態を調べた。 さらに、 各試料の表面を硝酸アルコ ールで軽くエッチングした後に膜表面を SEM (走査型電子顕微鏡） によつ て観察し、 その画像から前述の測定法により平均結晶粒径を求めた。 [0058] The magnetic properties of each sample were measured using a superconducting VSM (vibrating sample magnetometer) and applying a magnetic field of ± 6 T perpendicular to the film surface. Thereafter, the alignment direction of performing X-ray diffraction N d 2 F e 14 B crystals of each sample, and the multilayered sample was examined solid solution state into N d 2 F e 14 B crystal grains of T b element . Furthermore, after lightly etching the surface of each sample with alcoholic nitrate, the film surface was observed with a scanning electron microscope (SEM), and the average crystal grain size was determined from the image by the measurement method described above.
[0059] 表 2に、 各試料の熱処理温度、 平均結晶粒径、 磁気特性の関係を示す。 な お、 比較例試料 1、 2と同様に作製した N d_F e_B単層膜を熱処理しな い場合は、 平均結晶粒径が 0. 1 m、 保磁力が 784 k AZm、 残量磁化 が 1. 29 Tを示した。 表 2から明らかなように、 N d_F e_B単層膜を 熱処理した比較例試料 （1 ) 及び比較例試料 （2) は、 いずれも平均結晶粒 径が N d2F e14B化合物の単磁区粒径に相当する 0. 3 mに近く、 保磁力 が 700 k AZm前後と低い値を示した。 [0059] Table 2 shows the relationship between the heat treatment temperature, average crystal grain size, and magnetic properties of each sample. When the N d_F e_B single layer film prepared in the same way as Comparative Samples 1 and 2 is not heat-treated, the average crystal grain size is 0.1 m, the coercive force is 784 k AZm, and the residual magnetization is 1 29 T showed. As is clear from Table 2, the comparative sample (1) and the comparative sample (2) obtained by heat-treating the N d_F e_B single layer film are both single-domain of the N d 2 F e 14 B compound with an average grain size. The coercive force was as low as around 700 k AZm, close to 0.3 m corresponding to the particle size.
[0060] 一方、 積層膜を用いた本発明試料 （1 ) 〜 （5) では高温度の熱処理によ つて N d 2 F e 14B化合物の平均結晶粒径が 0. 5 m〜 28 mの範囲に成 長し、 且つ T b元素の N d 2 F e 14B結晶粒内への一部固溶と、 T bを主とす る結晶粒界相の形成効果によって保磁力が 1 060 k A/m〜 1 730 k A/ mと大幅に増加し、 本発明試料 （3) のそれは 1 730 kA/mであり、 比較 例試料 （1 ) の 724 kA/mの 2. 4倍に増加した。 [0060] On the other hand, in the samples (1) to (5) of the present invention using the laminated film, the average crystal grain size of the N d 2 Fe 14 B compound is 0.5 m to 28 m by the high-temperature heat treatment. The coercive force is 1 060 k due to the partial solid solution of the Tb element in the N d 2 F e 14 B crystal grains and the formation of a grain boundary phase mainly composed of T b. A / m to 1 730 k A / The value of the sample of the present invention (3) was 1 730 kA / m, which was 2.4 times that of 724 kA / m of the comparative sample (1).
[表 2]  [Table 2]
Figure imgf000020_0001
Figure imgf000020_0001
[0062] また、 本発明試料 （1 ) 〜 （5) の残留磁化は 1. 26丁〜 1. 32Tで あり、 比較例試料 （1 ) と比較して低下していないことから、 T b元素の多 くは N d 2 F e 14B結晶粒内へ固溶せずに主に結晶粒界相の形成に寄与してい ると考えられる。 この残留磁化の低下が小さいか、 又は若干増加する理由と しては、 保磁力が著しく増加することに伴って減磁曲線の角形性が向上する 結果、 残留磁化の低下が抑制されたためでもある。 [0062] Further, since the residual magnetizations of the samples (1) to (5) of the present invention are 1.26 to 1.32T, which is not lower than that of the comparative sample (1), the Tb element Most of them are considered to contribute mainly to the formation of the grain boundary phase without being dissolved in the N d 2 F e 14 B crystal grains. The reason why the decrease in remanent magnetization is small or slightly increased is that the decrease in remanent magnetization is suppressed as a result of the improvement in the squareness of the demagnetization curve as the coercive force increases significantly. .
[0063] さらに、 T bを予め含有させた合金 Bのターゲットを用いて成膜した比較 例試料 （3) では、 保磁力の増加は見られるが残留磁化の低下が大きいため に、 本発明で目的とする残留磁化の抑制効果が得られない。  [0063] Further, in the comparative sample (3) formed using the target of alloy B containing Tb in advance, the coercive force is increased, but the residual magnetization is greatly reduced. The intended effect of suppressing residual magnetization cannot be obtained.
[0064] 一方、 熱処理温度が低すぎる比較例試料 （4) では、 N d2F e 14B結晶粒 への T b元素の固溶と N d 2 F e 14Bの結晶成長が不充分なために保磁力の向 上がわずかしか認められない。 他方、 熱処理温度が高すぎる比較例試料 （5 ) では、 N d2F e14B結晶粒が大きすぎること、 及び薄膜が部分的に溶融し たために保磁力及び残留磁化が激減した。 [0064] On the other hand, in the comparative sample (4) where the heat treatment temperature is too low, the solid solution of Tb element in the N d 2 F e 14 B crystal grains and the crystal growth of N d 2 F e 14 B are insufficient. Therefore, only a slight improvement in coercive force is observed. On the other hand, in the comparative sample (5) in which the heat treatment temperature is too high, the coercive force and the remanent magnetization were drastically reduced because the N d 2 Fe 14 B crystal grains were too large and the thin film was partially melted.
[0065] 図 4に、 比較例試料 （1 ) 及び本発明試料 （3) の X線回折パターンを示 す。 図 4によれば、 C U-KQ?線を試料表面に当てた場合の N d 2 F e 14Bの (006) 面の回折ピークの位置が、 比較例試料では 44. 4度であるのに 対して、 本発明試料では 44. 7度にシフトしていることがわかる。 これはFIG. 4 shows the X-ray diffraction patterns of the comparative sample (1) and the inventive sample (3). According to Fig. 4, the position of the diffraction peak on the (006) plane of N d 2 F e 14 B when the C U-KQ? Line is applied to the sample surface is 44.4 degrees in the comparative sample. In On the other hand, it can be seen that the sample of the present invention is shifted to 44.7 degrees. this is
、 N dよリ原子半径の小さい T bが N d 2 F e 4 B結晶粒の N d原子の一部と 置換して固溶することによって、 結晶格子が縮んで回折線が高角度側にシフ 卜したことを意味しており、 積層膜の片方の T b膜の T b元素がもう一方の N d-F e- B膜と拡散反応を起こした証拠である。 By small T b I N d of Li atomic radius forms a solid solution by substituting a part of the N d atoms N d 2 F e 4 B grains, diffraction lines at high angle side shrinks crystal lattice This means that the Tb element in one of the Tb films in the multilayer film has caused a diffusion reaction with the other NdF e-B film.
[0066] なお、 薄膜中の N d及び T b元素含有量 （質量％) を、 単層膜の比較例試 料 （1 ) と比較例試料 （3) 、 及び積層膜の本発明試料 （3) について蛍光 X線分析法によって測定した結果、 下記のとおりであった。 [0066] The Nd and Tb element contents (% by mass) in the thin film were determined according to the comparative sample (1) for the monolayer film and the comparative sample (3), and the inventive sample (3 ) Was measured by X-ray fluorescence analysis, and the results were as follows.
比較例試料 （ 1 ) ； N d = 26. 2%  Comparative sample (1); N d = 26.2%
比較例試料 （3) ； N d = 24. 3%+T b = 1 0. 5% (合計 =34. 8 %)  Comparative sample (3); N d = 24. 3% + T b = 1 0.5% (total = 34.8%)
本発明試料 （3) ； N d = 24. 5%+T bが 1 0. 8% (合計 =35. 3 Sample of the present invention (3); N d = 24.5% + Tb is 10.8% (total = 35.3)
%) %)
実施例 2  Example 2
[0067] <スパッタリング法による薄膜磁石の作製、 その 2>  [0067] <Preparation of thin-film magnets by sputtering, Part 2>
ぐ比較例試料 6及び本発明試料 6の作製 >  Production of Comparative Sample 6 and Invention Sample 6>
R F出力を 1 5 OW、 DC出力を 25 OWに変更した以外は、 実施例 1と 同様の方法で比較例試料 6として厚さ 3 mの N d_F e _ B合金の単層膜 を作製し、 さらに同様の方法で、 本発明試料 6として厚さ 0. 2 mの T b 金属と、 厚さ 0. 8 mの N d_F e_B合金を繰り返し成膜し、 T b/N d -F e-B/T b/N d-F e-B/T b/N d-F e-B/T bの積層膜を製作 した。  A single layer film of N d_F e _ B alloy with a thickness of 3 m was fabricated as a comparative sample 6 in the same manner as in Example 1 except that the RF output was changed to 15 OW and the DC output was changed to 25 OW. Further, in the same manner, a Tb metal having a thickness of 0.2 m and an N d_F e_B alloy having a thickness of 0.8 m were repeatedly formed as Sample 6 of the present invention, and T b / N d -F eB / T A multilayer film of b / N dF eB / T b / N dF eB / T b was fabricated.
[0068] <本発明試料 7， 8の作製 >  [0068] <Preparation of inventive samples 7 and 8>
さらに、 本発明試料 6の作製に用いた T b金属の代わりに D y金属ターゲ ッ卜と P r金属ターゲッ卜をそれぞれ用いて、 本発明試料 6の作製と同様の 条件下で N d _ F e _ Bとの同構成の積層膜をそれぞれ製作した。  Furthermore, using a Dy metal target and a Pr metal target instead of the Tb metal used for the production of the inventive sample 6, respectively, under the same conditions as the production of the inventive sample 6, N d _ F Laminated films with the same structure as e_B were produced.
[0069] <熱処理 > [0069] <Heat treatment>
次に、 得られた単層膜及び積層膜をそれぞれ管状電気炉に装填し、 A rガ ス気流中で 1 0分間の熱処理を行った。 成膜及び熱処理条件を表 3に示す。 次いで、 実施例 1と同様に得られた試料の磁気特性を VSMによって、 平均 結晶粒径を S E Mによって測定した。 Next, the obtained monolayer film and laminated film are loaded into a tubular electric furnace, respectively, and Ar gas Heat treatment was performed for 10 minutes in the air stream. The film formation and heat treatment conditions are shown in Table 3. Next, the magnetic properties of the sample obtained in the same manner as in Example 1 were measured by VSM, and the average crystal grain size was measured by SEM.
[0070] ほ 3] [0070] Ho 3]
Figure imgf000022_0001
Figure imgf000022_0001
[0071] 表 4に、 各試料の平均結晶粒径と磁気特性の関係を示す。 表 4から、 本発 明試料 （5) ~ (7) は比較例試料 （6) に比べて、 高い保磁力と大きなェ ネルギ一積が得られ、 N d_F e— B単層膜に対して T b， Dy, P rいず れの金属を積層させても磁気特性の大幅な向上をもたらすことが明らかにな つた o [0071] Table 4 shows the relationship between the average crystal grain size of each sample and the magnetic properties. From Table 4, the present invention samples (5) to (7) have higher coercive force and larger energy volume than the comparative sample (6). It has been clarified that even if any of Tb, Dy, and Pr is laminated, the magnetic properties are greatly improved.
[0072] [表 4]  [0072] [Table 4]
Figure imgf000022_0002
実施例 3
Figure imgf000022_0002
Example 3
<スパッタリング法による薄膜磁石の作製、 その 3>  <Fabrication of thin film magnets by sputtering, part 3>
ぐ比較例試料 7〜 9及び本発明試料 9〜 1 4の作製 >  Production of Comparative Samples 7-9 and Invention Samples 9-14>
実施例 1で用いた N d_F e— B合金 （合金 A) ターゲッ卜を用い、 装置 内圧力を 3 Paとし、 SUS平板面の温度を 350°C、 3「出カを1 00 、 DC出力を 25 OWとした他は実施例 1と同様の方法で厚さ 25 mの N d_F e_B単層膜を製作した。 さらに、 実施例 1で用いた T bターゲット の代わりに 90 % D y _ 1 0 % C o組成 （単位は質量％) の合金ターゲッ卜 を用い、 厚さ 0. 0 1 m〜0. 8 mの D y _C o金属と、 厚さ 2 mの N d - F e _B合金を各 1 0回順次成膜し、 D y_Coと N d _ F e _Bの 積層膜を製作した。 Using the N d_F e- B alloy (alloy A) target used in Example 1, the internal pressure of the device is 3 Pa, the temperature of the SUS flat plate surface is 350 ° C, and 3 “output is 100, DC output is A 25-m-thick N d_F e_B single-layer film was fabricated in the same manner as in Example 1, except that 25 OW was used, and 90% D y _ 1 0 instead of the T b target used in Example 1. Alloy target with% Co composition (unit: mass%) Dy_Co metal with a thickness of 0.01 m to 0.8 m and Nd-Fe_B alloy with a thickness of 2 m were sequentially deposited 10 times each, and Dy_Co and Nd A multilayer film of _F e _B was manufactured.
[0074] <熱処理 >  [0074] <Heat treatment>
次に、 得られた単層膜及び積層膜をそれぞれ 2 X 1 0_4P a以下に排気した 真空炉に装填し、 30分間の熱処理を行った。 成膜及び熱処理条件を表 5に 示す。 単層膜を熱処理したものを比較例試料 （7) とした。 積層膜を熱処理 したものについては、 D y— Co膜厚が 0. 0 1， 0. 02， 0. 05， 0 . 1， 0. 2， 0. 4， 0. 6, 0. 8 mの順に、 比較例試料 （8) 、 本 発明試料 （9) 〜 （1 4) 、 比較例試料 （9) とした。 次いで、 各試料の磁 気特性を V S Mによって測定し、 N d及び D yの含有量を蛍光 X線分析によ つて求めた。 Then, the obtained single-layer film and a laminated film was loaded into a vacuum furnace which is evacuated below each 2 X 1 0_ 4 P a, a heat treatment was carried out for 30 minutes. Table 5 shows the film formation and heat treatment conditions. A heat-treated single layer film was used as a comparative sample (7). In the case of heat treatment of the laminated film, the Dy-Co film thickness is 0.0 1, 0, 02, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8 m. In this order, the comparative sample (8), the inventive samples (9) to (14), and the comparative sample (9) were used. Next, the magnetic properties of each sample were measured by VSM, and the contents of Nd and Dy were determined by fluorescent X-ray analysis.
[0075] [表 5]  [0075] [Table 5]
Figure imgf000023_0001
Figure imgf000023_0001
[0076] 表 6に、 N d _ F e _B/D y _C o積層試料の、 D y—Co膜厚に対する [0076] Table 6 shows the N d _F e _B / D y _C o laminated sample with respect to the D y—Co film thickness.
D y及びD yとN dの合計含有量、 及び磁気特性との関係を示す。 The relationship between the total content of Dy and Dy and Nd, and the magnetic properties is shown.
[0077] [表 6] [0077] [Table 6]
Dy— Co膜厚 Dya有 Dy+NcJ含有量 保磁力 Hcj 残留磁化 BrDy— Co film thickness Dya existence Dy + NcJ content Coercive force Hcj Residual magnetization Br
( /m) (%) ί%) (kA/m) (T) 比較例試料 (7) 0 0 26.5 650 1.31 比較例試料（8〕 0.01 05 270 750 1.33 本発明試料（9) 0.02 1.0 27.2 1030 1.33 本発明試料（10) 0.05 2.6 28.3 1160 132 本発明試料（11) 0.1 5.1 29.6 1280 1.30 本発明試料（12) 0.2 97 33.2 1400 1.29 本発明試料（13) 0.4 183 39.5 1610 1.27 本発明試料（14) 0.6 25.2 44.2 !680 1.24 比較例試料（9) 0.8 30.7 49.1 1670 1.15 [0078] また、 図 5に、 Dy—Co膜厚に対する磁気特性の関係グラフを、 N d_ F e_B単層膜試料と比較して示す。 表 6から、 単層膜の比較例試料 （7) に対して、 積層膜の本発明試料 （9) 〜 （1 4) は Dyの導入によって保磁 力が著しく増加し、 残留磁化の低下も小さいことが明らかになり、 Dy金属 のみでなく Coを含んでも良好な磁気特性が得られることがわかった。 しか し、 D y—Co膜厚が非常に薄い 0. 01 mの比較例試料 （8) は、 Dy 含有量が 1質量％未満であるために保磁力の効果的な増加が見られなかった 。 また、 Dy_Co膜厚が厚すぎる比較例試料 （9) は、 Dy含有量が好ま しい範囲の 30質量％を超えるとともに、 N dとの合計含有量も 45質量％ を超えたため、 残留磁化の低下が大きく、 且つ保磁力の増加が停滞した。 実施例 4 (/ m) (%) ί%) (kA / m) (T) Comparative sample (7) 0 0 26.5 650 1.31 Comparative sample (8) 0.01 05 270 750 1.33 Invention sample (9) 0.02 1.0 27.2 1030 1.33 Sample of the present invention (10) 0.05 2.6 28.3 1160 132 Sample of the present invention (11) 0.1 5.1 29.6 1280 1.30 Sample of the present invention (12) 0.2 97 33.2 1400 1.29 Sample of the present invention (13) 0.4 183 39.5 1610 1.27 Sample of the present invention (14 ) 0.6 25.2 44.2! 680 1.24 Comparative sample (9) 0.8 30.7 49.1 1670 1.15 [0078] FIG. 5 shows a graph of the relationship between the magnetic properties and the Dy—Co film thickness in comparison with the N d — F e — B single layer film sample. From Table 6, it can be seen that compared to the single layer film comparative sample (7), the laminated film samples (9) to (14) have a significantly increased coercive force due to the introduction of Dy and a decrease in residual magnetization. It became clear that it was small, and it was found that good magnetic properties could be obtained not only with Dy metal but also with Co. However, the comparative sample (8) with a very thin D y—Co film of 0.01 m did not show an effective increase in coercive force because the Dy content was less than 1% by mass. . In addition, the comparative sample (9) whose Dy_Co film thickness is too thick exceeded 30% by mass in the preferred Dy content range, and the total content with Nd also exceeded 45% by mass. And the increase in coercive force stagnated. Example 4
[0079] <パルスレーザーデポジション （P LD) 法による薄膜磁石の作製 >  [0079] <Manufacture of thin film magnet by pulsed laser deposition (P LD) method>
パルスレーザーデポジション （P LD) 装置の減圧容器 （チャンバ一） 内 に、 直径 4 Ommの 28%N d _ 1. 0%B—残部 F e (単位は質量％) の 円板状合金ターゲットと、 同寸法の T b金属ターゲットを装着し、 さらに該 合金ターゲット上に一辺が 5 mmの四角片形状をした Co, C r， C u, A I， V， N bの各金属片を、 適宜選択して所定個数積載した。 また、 溶剤脱 脂と酸洗浄をした長さ 8mm、 幅 5mm、 厚さ 0. 3mmの T a基板を、 取 リ付け治具を用いてアルミナ基盤上に固定設置した。  In the reduced pressure vessel (chamber one) of the pulse laser deposition (P LD) device, a disk-shaped alloy target with 28% N d _1.0% B—balance Fe (unit: mass%) with a diameter of 4 Omm Co, Cr, Cu, AI, V, and Nb metal pieces, each of which is a square piece with a side of 5 mm on the alloy target, are selected as appropriate. Then, a predetermined number was loaded. Also, a Ta substrate 8 mm long, 5 mm wide, and 0.3 mm thick after solvent degreasing and acid cleaning was fixed on the alumina substrate using a mounting jig.
[0080] <比較例試料 1 0、 11及び本発明試料 1 5〜 22の作製 >  <Preparation of Comparative Samples 10 and 11 and Invention Samples 15 to 22>
最初に、 チャンバ一内を 1 X 1 0-4 P aまで排気後に、 N d ： Y AGレーザ 一を N d_F e_Bターゲッ卜に照射し、 T a基板上に単層膜を作製した。 得られた単層膜をチャンバ一から取り出した。 次に、 T bターゲットと Cu 金属片を積載した N d _ F e _ Bターゲットに所定時間ずつ交互にレーザー を照射して Cu元素を解離放出させ、 T a基板上に積層膜を作製した。 得ら れた積層膜をチャンバ一から取り出した。 同様の方法で順次金属片を A I， V， N b, C r, Coに変更して T a基板上に積層膜を作製した。 なお、 添 加量の調整は金属片の使用枚数によって行なった。 例えば、 添加金属量がお よそ 2質量％の場合は金属片 1枚を、 5〜 6質量％の場合は金属片 3枚を使 用した。 First, after evacuating the inside of the chamber to 1 X 10-4 P a, the N d: Y AG laser was irradiated to the N d_F e_B target to produce a single layer film on the Ta substrate. The obtained monolayer film was taken out from the chamber. Next, the Nd_Fe_B target loaded with the Tb target and Cu metal pieces was irradiated with laser alternately for a predetermined time to dissociate and release the Cu element, and a laminated film was produced on the Ta substrate. The obtained laminated film was taken out from the chamber. In the same way, the metal pieces were sequentially changed to AI, V, Nb, Cr, and Co, and a laminated film was fabricated on the Ta substrate. The addition amount was adjusted according to the number of metal pieces used. For example, the amount of added metal In the case of 2% by mass, one metal piece was used, and in the case of 5-6% by mass, 3 metal pieces were used.
[0081] なお、 ターゲットと基板間の距離は 25mmとし、 レーザー出力を一定と して T bを 0. 3 m、 N d_F e_B-X (ここで、 Xは、 Co, C r , C u, A I , V， N b, Wから選ばれる添加金属を 1 mとし、 各層を積み上 げて 20層とし、 最後に T bを成膜して合計 21層の積層膜を作製した。  [0081] Note that the distance between the target and the substrate is 25 mm, the laser output is constant, and T b is 0.3 m, N d_F e_B-X (where X is Co, C r, Cu, The additive metal selected from AI, V, Nb, and W was 1 m, each layer was stacked to form 20 layers, and finally Tb was formed to produce a total of 21 layers.
[0082] <熱処理 >  [0082] <Heat treatment>
得られた積層膜を 2 X 1 0_4P a以下に排気した真空炉に装填し、 30分間 の熱処理を行った。 成膜及び熱処理条件を表 7に示す。 N d_F e_B単層 膜を熱処理したものを比較例試料 （1 0) 、 Coを過剰に含有する積層膜を 熱処理したものを比較例試料 （1 1 ) とし、 各金属を添加した積層膜を熱処 理したものを本発明試料 （1 5) 〜 （22) とした。 次いで、 各試料の磁気 特性を VSMによって測定し、 各添加金属の含有量を蛍光 X線分析によって 求めた。 The resulting loaded with stacked film in a vacuum furnace which is evacuated to less than 2 X 1 0_ 4 P a, a heat treatment was carried out for 30 minutes. Table 7 shows the film formation and heat treatment conditions. N d_F e_B single layer film heat treated as a comparative sample (10) and heat treated multilayer film containing Co as a comparative sample (1 1). The processed samples were designated as inventive samples (15) to (22). Next, the magnetic properties of each sample were measured by VSM, and the content of each additive metal was determined by fluorescent X-ray analysis.
[0083] [表 7]  [0083] [Table 7]
Figure imgf000025_0001
Figure imgf000025_0001
[0084] 表 8に、 単層膜、 及び添加金属を含む積層膜を熱処理した場合の磁気特性 を示す。 表 8から、 単層膜の比較例試料 （1 0) に対して、 積層膜の本発明 試料 （1 5) 〜 （23) は各添加金属を導入しても保磁力がおよそ 2〜3倍 に増加することから、 添加金属の一部は N d2F e14B結晶粒に固溶し、 他方 はその結晶粒界相に固溶するか、 又は化合物を形成することによって、 保磁 力を効果的に向上させたと推測される。 [0084] Table 8 shows the magnetic characteristics when the single-layer film and the laminated film containing the additive metal are heat-treated. From Table 8, the sample of the present invention (15) to (23) of the laminated film is approximately 2 to 3 times the coercive force even when each additive metal is introduced, compared with the comparative sample (10) of the single layer film. Part of the added metal is dissolved in the N d 2 F e 14 B crystal grains, and the other is dissolved in the grain boundary phase, or a coercive force is formed by forming a compound. It is presumed that this was effectively improved.
[0085] C oを含有した試料では、 他の添加金属と比較してやや保磁力が小さいも のの、 充分大きな値を示しており、 別効果としてキュリー温度を向上させる 働きがある。 ただし、 比較例試料 （1 1 ) のように Co含有量が約 35質量 %になると保磁力の低下が大きくなるため、 これら添加金属の含有量は 30 質量％を超えない範囲が好ましい。 なお、 表 8中の残留磁化の値がいずれも 1 Tに満たない理由は、 各試料の X線回折による解析結果、 Nd2Fe14B結 晶が膜内において等方的に分散した状態となっているためであり、 その理由 としては成膜中の T a基板を加熱していないためと推察される。 [0085] The sample containing Co shows a sufficiently large value although it has a slightly smaller coercive force than other additive metals, and improves the Curie temperature as another effect. There is work. However, when the Co content is about 35% by mass as in the comparative sample (11), the coercive force decreases greatly, so the content of these added metals is preferably within a range not exceeding 30% by mass. The reason why the values of remanent magnetization in Table 8 are all less than 1 T is that Nd 2 Fe 14 B crystals are isotropically dispersed in the film as a result of X-ray diffraction analysis of each sample. This is probably because the Ta substrate during film formation was not heated.
[0086] [表 8] [0086] [Table 8]
Figure imgf000026_0001
実施例 5
Figure imgf000026_0001
Example 5
[0087] <スパッタリング法による薄膜磁石の作製、 その 4>  [0087] <Fabrication of thin film magnet by sputtering method, Part 4>
外径 6 Omm、 内径 34mm、 厚さ 1 2 mmの 28 % N d - 1. 0 % B - 残部 F e (単位は質量％) の円環状合金ターゲットと、 同寸法の T b金属タ ーゲットを製作し、 他方、 直径が 0. 6 mmで長さ 1 2 mmのアルミナシャ フトを基材とした。 スパッタリング装置として公知の 3次元スパッタリング 装置を用いた。 この 3次元スパッタリング装置の構成と原理については、 特 開 2004-304038号公報に開示されている。 3次元スパッタリング装置の左室に 、 対向する T bターゲットの中間に高周波発生用 Cuコイルを配置し、 右室 にも同様に N d _ F e—Bターゲットと C uコイルを配置した。 また、 左室 の左側から右側に伸びるモータ回転軸の先端部にアルミナシャフ卜を取り付 けた。 An annular alloy target with an outer diameter of 6 Omm, an inner diameter of 34 mm, and a thickness of 12 mm, 28% Nd-1.0% B-balance Fe (unit: mass%), and a Tb metal target of the same dimensions On the other hand, an alumina shaft having a diameter of 0.6 mm and a length of 12 mm was used as a base material. A known three-dimensional sputtering apparatus was used as the sputtering apparatus. The configuration and principle of this three-dimensional sputtering apparatus are disclosed in Japanese Patent Publication No. 2004-304038. In the left chamber of the 3D sputtering system, a Cu coil for high frequency generation was placed in the middle of the opposing Tb target, and an Nd_Fe-B target and a Cu coil were also placed in the right chamber. Left ventricle An alumina shaft was attached to the tip of the motor rotating shaft extending from the left side to the right side.
[0088] ぐ比較例試料 1 2の作製 >  [0088] Production of Gu Comparative Example Sample 1 2>
スパッタ装置内を 5 X 1 0_5Paまで真空排気した後、 A「ガスを導入して 装置内圧力を 3 Paに維持した。 最初に、 対向する N d_F e_Bターゲッ 卜の中間位置にアルミナシャフ卜を位置決めし、 6 r pmでシャフ卜を回転 させながら、 RF出力 1 5 OWと DC出力 30 OWを加えて厚さ 80 mの N d-F e _ B合金の単層膜を成膜した。 After evacuating the inside of the sputtering system to 5 X 1 0_ 5 Pa, A “Gas was introduced and the pressure inside the system was maintained at 3 Pa. First, the alumina shaft was placed in the middle of the opposing N d_F e_B target 卜. Was positioned, and an RF output of 15 OW and a DC output of 30 OW were added while rotating the shaft at 6 rpm to form a single-layer film of NdF e _ B alloy with a thickness of 80 m.
[0089] <比較例試料 1 3及び本発明試料 24〜 30の作製 >  <Preparation of Comparative Sample 1 3 and Invention Samples 24-30>
一方、 対向する T bターゲッ卜の中間位置にまず該シャフ卜を位置決めし 、 比較例試料 1 2の作製と同じ回転数と成膜出力下で厚さ 0. 2 の丁 0 膜を成膜し、 弓 Iき続いてモータ取り付け棒を自動的に右に移送して該シャフ 卜を N d_F e_Bターゲッ卜の中間に位置決めし、 厚さ 0. 8 mのN d _F e_B膜を成膜し、 再度このシャフトを左に移送して厚さ 0. 2 mの T bを成膜して、 総厚 1. 2 mの積層膜を製作した。 さらに、 同様の方法 によって積層数を増やし、 総厚が約 5， 1 0， 40， 80， 1 60， 280 ， 360 mの各積層膜を製作した。  On the other hand, the shuff rod is first positioned at an intermediate position between the opposing Tb targets, and a film having a thickness of 0.2 is formed under the same rotational speed and film deposition output as those of Comparative Example Sample 12. , Bow I, then the motor mounting rod is automatically moved to the right to position the shaft N in the middle of the N d_F e_B target, and a 0.8 m thick N d _F e_B film is deposited, The shaft was again transferred to the left to form a 0.2 m thick Tb film to produce a laminated film with a total thickness of 1.2 m. Furthermore, the number of layers was increased by the same method, and each layered film with total thickness of about 5, 10, 40, 80, 160, 280, 360 m was manufactured.
[0090] ぐ熱処理 >  [0090] Gu heat treatment>
得られた単層及び積層膜を 2 X 1 0_4P a以下に排気した真空炉に装填し 3 0分間の熱処理を行った。 成膜及び熱処理条件を表 9に示す。 The resulting heat-treated in a single layer and multilayer films 2 X 1 0_ 4 was loaded into a vacuum furnace was evacuated to less than P a 3 0 min was performed. Table 9 shows the film formation and heat treatment conditions.
[0091] [表 9]  [0091] [Table 9]
Figure imgf000027_0001
積層膜を熱処理したものを、 膜厚が 1. 2， 5， 1 0， 40， 80， 1 6 0， 280 mの順に従って、 本発明試料 （24) 〜 （30) とし、 膜厚が 360 mのものを比較例試料 （1 3) とした。 次いで、 成膜された円筒状 試料の径方向に磁界を掃引させながらその磁気特性を V S Mによって測定し た。 図 6に、 単層膜及び積層膜の総膜厚に対する磁気特性の関係を示す。 図 6から、 8 0 mの膜厚に関して、 図中黒印で示した単層膜の比較例試料 （ 1 2 ) に対して、 積層膜の本発明試料 （2 8 ) では残留磁化の低下はわずか で、 保磁力が著しく増加した。
Figure imgf000027_0001
The heat treatment of the laminated film is made according to the samples of the present invention (24) to (30) in the order of film thicknesses of 1.2, 5, 10, 40, 80, 160, 280 m. The sample with m was used as a comparative sample (13). Next, the deposited cylindrical shape The magnetic properties were measured by VSM while sweeping the magnetic field in the radial direction of the sample. Figure 6 shows the relationship of the magnetic properties with respect to the total film thickness of single-layer films and laminated films. From Fig. 6, regarding the film thickness of 80 m, the decrease in the remanent magnetization in the sample of the present invention (2 8) of the laminated film is different from the comparative sample (1 2) of the single layer film indicated by the black mark in the figure. Even slightly, the coercive force increased significantly.
[0093] また、 本発明試料 （2 4 ) 〜 （3 0 ) では、 いずれも比較的高い残留磁化 を保ちながら高保磁力が得られており、 超小型モータ等の駆動用などに充分 適用可能な磁気特性が得られた。 しかし、 総膜厚が 3 6 0 mになると結晶 性の低下や結晶配向性の乱れなどに起因する磁気特性の低下が見られるため 、 好適には 3 0 0 m以下とするのが良い。 [0093] In addition, all of the samples (24) to (30) of the present invention have a high coercive force while maintaining a relatively high remanent magnetization, and are sufficiently applicable for driving micro motors and the like. Magnetic properties were obtained. However, when the total film thickness is 3600 m, a decrease in crystallinity and a decrease in magnetic properties due to disorder of crystal orientation are observed. Therefore, the total thickness is preferably set to 300 m or less.
[0094] なお、 本発明試料 （2 8 ) について、 膜の長手方向の磁気測定を行った結 果、 径方向と比較して残留磁化がその 1 Z 3程度であったことから、 該試料 では N d 2 F e 1 4 B結晶が膜の円周ラジアル方向に配向していることが明らか になった。 [0094] As for the sample of the present invention (2 8), as a result of the magnetic measurement in the longitudinal direction of the film, the residual magnetization was about 1 Z 3 as compared with the radial direction. It became clear that the N d 2 F e 14 B crystal was oriented in the circumferential radial direction of the film.
産業上の利用可能性  Industrial applicability
[0095] マイクロマシンを駆動させるためのァクチユエータや微小な磁気センサ用 等々として、 小型で高性能な永久磁石が必要とされている。 本発明は、 上記 の強い要請に基づき、 所望の高保磁力高性能の薄膜永久磁石を提供するもの で、 マイクロマシンなど各種応用機器に搭載されることにより、 機器の高出 力化、 小型化、 さらに高保磁力特性に基づく様々な使用環境での耐熱安定性 の実現に大いに貢献する。 また、 本発明の薄膜永久磁石は、 高い保磁力が得 られると同時に、 比較的大きな結晶粒径を有する N d 2 F e 1 4 B結晶粒からな る結晶相と該結晶粒の周囲又は/及び該結晶相の層間に存在する M又は M合金 の結晶粒界相の複合組織構造によって着磁性が向上し、 応用機器への使用が 容易となる。 There is a need for a small, high-performance permanent magnet for an actuator for driving a micromachine, a minute magnetic sensor, and the like. The present invention provides a thin film permanent magnet having a desired high coercive force and high performance based on the above-mentioned strong demand. By being mounted on various application devices such as a micromachine, the device has a high output and a small size. It greatly contributes to the realization of heat-resistant stability in various usage environments based on high coercive force characteristics. In addition, the thin film permanent magnet of the present invention can obtain a high coercive force and, at the same time, a crystal phase composed of N d 2 F e 14 B crystal grains having a relatively large crystal grain size and / or around the crystal grains. In addition, the magnetic structure is improved by the composite structure of the grain boundary phase of M or M alloy existing between the crystal phases, and the use in the applied equipment becomes easy.

Claims

請求の範囲 The scope of the claims
[1] M又は M合金 （ただし、 Mは、 P r， Dy， T b, H oの一種又は二種以 上） 膜と N d _ F e _B系合金膜とが交互に積層された 3層以上の積層構造 を熱処理して M又は M合金成分と N d— F e— B系合金成分を相互拡散させ てなる薄膜希土類磁石であって、  [1] M or M alloy (where M is one or more of Pr, Dy, Tb, and Ho) Films and Nd_Fe_B alloy films are laminated alternately 3 A thin-film rare earth magnet obtained by heat-treating a laminated structure of more than one layer and interdiffusing M or M alloy component and N d- F e- B alloy component,
該熱処理によリ N d 2 F e 4 B結晶粒の表面部に M元素が N dと置換して固溶 された （N d、 M) 2 F e 14B結晶が形成され、 かつ N d 2 F e 14B結晶粒の 粒界に （N d、 M) 2 F e 14B結晶と界面を接して M又は M合金からなる結晶 粒界相が形成されてなることを特徴とする薄膜希土類磁石。 The heat element M by the surface portion of the Li N d 2 F e 4 B crystal grains process is dissolved by replacing the N d (N d, M) 2 F e 14 B crystals are formed, and N d A thin film rare earth characterized in that a crystal grain boundary phase made of M or M alloy is formed at the interface of (N d, M) 2 F e 14 B crystal at the grain boundary of 2 F e 14 B crystal grain magnet.
[2] 薄膜の厚さ方向に N d 2 F e 14B結晶相が層状に形成され、 該結晶相の層間 に （N d、 M) 2 F e 14B結晶と界面を接して M又は M合金からなる結晶粒界 相が形成されてなることを特徴とする請求項 1記載の薄膜希土類磁石。 [2] An N d 2 F e 14 B crystal phase is formed in layers in the thickness direction of the thin film, and the M or M is in contact with the (N d, M) 2 F e 14 B crystal between the crystal phases. 2. The thin-film rare earth magnet according to claim 1, wherein a crystal grain boundary phase made of an alloy is formed.
[3] 薄膜の厚さ方向に N d 2 F e 14 B結晶相が層状に形成され、 N d 2 F e 4 B 結晶粒の周囲に （N d、 M) 2 f e 14 B結晶と界面を接して N d 2 F e ι 4
Figure imgf000029_0001
晶粒を取リ囲む M又は M合金からなる結晶粒界相が形成されてなることを特 徴とする請求項 1記載の薄膜希土類磁石。 [3] N d 2 F e 14 B crystal phase is formed in layers in the thickness direction of the thin film, and (N d, M) 2 f e 14 B crystal and interface around the N d 2 F e 4 B crystal grains N d 2 F e ι 4
Figure imgf000029_0001
2. The thin film rare earth magnet according to claim 1, wherein a crystal grain boundary phase made of M or an M alloy surrounding the crystal grains is formed.
[4] N d 2 F e 14B結晶粒の平均結晶粒径が 0. 5 m〜 30 mであることを 特徴とする請求項 1記載の薄膜希土類磁石。 [4] The thin film rare earth magnet according to [1], wherein the average grain size of the N d 2 Fe 14 B crystal grains is 0.5 m to 30 m.
[5] N d_F e_B系合金がN d2F e14B化合物からなリ、 薄膜中の M元素の 含有量が 1〜 30質量％であり、 且つ N dと M元素の合計含有量が 28〜 4 5質量％であることを特徴とする請求項 1記載の薄膜希土類磁石。 [5] The N d_F e_B alloy is made of an N d 2 F e 14 B compound, the content of M element in the thin film is 1 to 30% by mass, and the total content of N d and M element is 28 The thin-film rare earth magnet according to claim 1, characterized in that it is ˜45 mass%.
[6] N d 2 F e 14B化合物の F eの 30質量％未満が C o， N i， T i， V， C r , C u, A I , Z n， G a, V， Mo, N b, T a, Wの一種又は 2種以 上の元素で置換されていることを特徴とする請求項 5記載の薄膜希土類磁石 [6] Less than 30% by mass of Fe in N d 2 F e 14 B compound is Co, Ni, Ti, V, Cr, Cu, AI, Zn, Ga, V, Mo, N 6. The thin film rare earth magnet according to claim 5, wherein the thin film rare earth magnet is substituted with one or more elements of b, Ta, and W.
[7] 薄膜構成原料や成膜と熱処理工程から由来する不可避不純物を含むことを 特徴とする請求項 1記載の薄膜希土類磁石。 7. The thin-film rare earth magnet according to claim 1, further comprising inevitable impurities derived from the thin film constituting raw material and the film formation and heat treatment steps.
[8] 薄膜の厚さが 1 m〜300 mであることを特徴とする請求項 1記載の薄 膜希土類磁石。 8. The thin film according to claim 1, wherein the thin film has a thickness of 1 m to 300 m. Film rare earth magnet.
残留磁化 B rが 1. 26 T以上であることを特徴とする請求項 1記載の薄 膜希土類磁石。  2. The thin film rare earth magnet according to claim 1, wherein the residual magnetization B r is 1.26 T or more.
保磁力 H c jが 1 060 kAZm以上であることを特徴とする請求項 1記 載の薄膜希土類磁石。  The thin film rare earth magnet according to claim 1, wherein the coercive force H c j is 1 060 kAZm or more.
減圧容器内で物理的成膜法によリ、 N d _ F e _ B系合金と M金属又はそ の合金 （ただし、 Mは、 P r， Dy， T b, H oの一種又は二種以上） を交 互に積層して成膜し、 その後に 700〜1 1 00°Cの熱処理を行うことによ リ M又は M合金成分と N d— F e— B系合金成分を相互拡散させて、 該 N d 2 F e 14B結晶粒の表面部に M元素が N dと置換して固溶された （N d、 M) 2 F e14B結晶を形成し、 かつ N d 2 F e 14B結晶の粒界に （N d、 M) 2 F e 14 B結晶と界面を接して M又は M合金からなる結晶粒界相を形成することを 特徴とする請求項 1記載の薄膜希土類磁石の製造方法。 N d _ F e _ B alloy and M metal or its alloys (where M is one or two of Pr, Dy, Tb, Ho) Are laminated together, and then heat-treated at 700 to 1100 ° C to allow M or M alloy components and N d-Fe-B-based alloy components to interdiffuse. The element M is substituted with N d to form a solid solution (N d, M) 2 F e 14 B crystal on the surface of the N d 2 F e 14 B crystal grains, and N d 2 F 2. The thin film rare earth according to claim 1, wherein a grain boundary phase made of M or an M alloy is formed by contacting an interface with the (N d, M) 2 F e 14 B crystal at the grain boundary of the e 14 B crystal. Magnet manufacturing method.
最初に 400〜 650°Cで N d - F e _B系膜中に N d 2 F e 14B化合物の結 晶生成を行い、 その後に 700〜1 1 00°Cで熱処理する 2段階の熱処理を 行うことを特徴とする請求項 1 1記載の薄膜希土類磁石の製造方法。 First, a crystal of N d 2 Fe 14 B is formed in the N d -F e _B film at 400 to 650 ° C, followed by heat treatment at 700 to 110 ° C. The method for producing a thin-film rare earth magnet according to claim 11, wherein the method is performed.
N d _ F e— B系合金膜の一層の膜厚を 0. 05 m〜 50 mとし、 N d _ F e _B系合金と M金属又はその合金の膜厚比を 99 ： 1〜60 ： 40 として成膜することを特徴とする請求項 1 1又は 1 2記載の薄膜希土類磁石 の製造方法。  The film thickness of one layer of N d _F e—B-based alloy film is 0.05 m to 50 m, and the film thickness ratio of N d _F e _B-based alloy to M metal or its alloy is 99: 1 to 60: The method for producing a thin-film rare earth magnet according to claim 11 or 12, wherein the film is formed as 40.
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