WO2000049608A1 - Magnetic recording medium with improved performance properties and methods - Google Patents
Magnetic recording medium with improved performance properties and methods Download PDFInfo
- Publication number
- WO2000049608A1 WO2000049608A1 PCT/US2000/003894 US0003894W WO0049608A1 WO 2000049608 A1 WO2000049608 A1 WO 2000049608A1 US 0003894 W US0003894 W US 0003894W WO 0049608 A1 WO0049608 A1 WO 0049608A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- magnetic
- recording medium
- oxygen
- magnetic layer
- plasma
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims description 15
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 27
- 239000001301 oxygen Substances 0.000 claims abstract description 27
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 27
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000000203 mixture Substances 0.000 claims abstract description 15
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims abstract description 14
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 14
- 239000000758 substrate Substances 0.000 claims abstract description 13
- 229910052786 argon Inorganic materials 0.000 claims abstract description 7
- 229910017052 cobalt Inorganic materials 0.000 claims abstract description 7
- 239000010941 cobalt Substances 0.000 claims abstract description 7
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims abstract description 7
- 101000642333 Homo sapiens Survival of motor neuron-related-splicing factor 30 Proteins 0.000 claims description 4
- 102100036412 Survival of motor neuron-related-splicing factor 30 Human genes 0.000 claims description 4
- 229910000428 cobalt oxide Inorganic materials 0.000 claims description 3
- IVMYJDGYRUAWML-UHFFFAOYSA-N cobalt(ii) oxide Chemical compound [Co]=O IVMYJDGYRUAWML-UHFFFAOYSA-N 0.000 claims description 3
- 239000001307 helium Substances 0.000 claims description 2
- 229910052734 helium Inorganic materials 0.000 claims description 2
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 2
- 229910052743 krypton Inorganic materials 0.000 claims description 2
- DNNSSWSSYDEUBZ-UHFFFAOYSA-N krypton atom Chemical compound [Kr] DNNSSWSSYDEUBZ-UHFFFAOYSA-N 0.000 claims description 2
- 229910052754 neon Inorganic materials 0.000 claims description 2
- GKAOGPIIYCISHV-UHFFFAOYSA-N neon atom Chemical compound [Ne] GKAOGPIIYCISHV-UHFFFAOYSA-N 0.000 claims description 2
- 229910052724 xenon Inorganic materials 0.000 claims description 2
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims 1
- 238000004381 surface treatment Methods 0.000 abstract description 4
- 239000000314 lubricant Substances 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000004544 sputter deposition Methods 0.000 description 4
- 230000007704 transition Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 239000007789 gas Substances 0.000 description 2
- 229910001149 41xx steel Inorganic materials 0.000 description 1
- 229910052580 B4C Inorganic materials 0.000 description 1
- 229910000531 Co alloy Inorganic materials 0.000 description 1
- 229910000599 Cr alloy Inorganic materials 0.000 description 1
- 229910000861 Mg alloy Inorganic materials 0.000 description 1
- 229910000943 NiAl Inorganic materials 0.000 description 1
- NPXOKRUENSOPAO-UHFFFAOYSA-N Raney nickel Chemical compound [Al].[Ni] NPXOKRUENSOPAO-UHFFFAOYSA-N 0.000 description 1
- VVTSZOCINPYFDP-UHFFFAOYSA-N [O].[Ar] Chemical compound [O].[Ar] VVTSZOCINPYFDP-UHFFFAOYSA-N 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- SNAAJJQQZSMGQD-UHFFFAOYSA-N aluminum magnesium Chemical compound [Mg].[Al] SNAAJJQQZSMGQD-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000003618 dip coating Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000002241 glass-ceramic Substances 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/64—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent
- G11B5/65—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition
- G11B5/658—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition containing oxygen, e.g. molecular oxygen or magnetic oxide
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/72—Protective coatings, e.g. anti-static or antifriction
- G11B5/727—Inorganic carbon protective coating, e.g. graphite, diamond like carbon or doped carbon
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
- G11B5/8408—Processes or apparatus specially adapted for manufacturing record carriers protecting the magnetic layer
Definitions
- Magnetic recording media are constantly being improved to increase data density. Key features to achieving high linear density for magnetic recording media are high playback signal, narrow pulse width, high signal-to-media noise ratio and good overwrite. To meet these criteria, the magnetic media requires high coercivity (Hr), low remanence-thickness product (M r *), high coercive squareness (S*), high remanence squareness (SQ) and thin magnetic layer.
- Hr high coercivity
- M r * low remanence-thickness product
- S* high coercive squareness
- SQ high remanence squareness
- Hr and M r * are specified by the customer of disk drive company.
- a disk manufacturing company it is a challenge to obtain media with high S* and SQ, thin magnetic layer, and meanwhile, to maintain high signal-to-media noise ratio and good overwrite. From mass production point of view, a stable process is required to make consistent products.
- a conventional magnetic recording disk structure 2 is shown in Fig. 1.
- Structure 2 includes a substrate 4, a first seed layer 6 (optional), a second seed layer 8 (optional), an underlayer 10, a transition magnetic layer 12 (optional), a magnetic layer 14, an overcoat layer 16 and a lubricant layer 18.
- the composition of overcoat layer 16 is typically carbon doped with H or N or both.
- the composition of magnetic layer 14 is typically Co alloys such as CoCrTa, CoCrTaPt, CoCrTaPtB, CoCrTaPtNb, etc.
- the transition magnetic layer 12 is an optional layer which provides a better lattice match transition between underlayer 10 and magnetic layer 14.
- the composition of transition magnetic layer 12 is similar to that of magnetic layer 14.
- the composition of underlayer 10 typically can be NiP, Cr and Cr alloys such as CrV, CrTi, CrMo, etc. Seed layers 6,8 are also optional layers. NiAl and NiP can be used for second seed layer 8 and MgO can be used for first seed layer 6.
- the materials of substrate 4 can be aluminum-magnesium alloys with a plated NiP layer, glass, glass-ceramic, ceramic, carbon, silicon, aluminum- boron-carbide alloys, etc.
- the present invention is directed to a magnetic recording medium with improved performance properties and methods. The invention improves magnetic properties and recording performance values for high density magnetic media and helps to stabilize the magnetic properties and recording performance values of the products using the media.
- the magnetic recording medium is of the type including a substrate, an overcoat layer and a magnetic layer therebetween.
- the magnetic layer preferably contains cobalt and the overcoat layer preferably contains carbon, as is conventional.
- the outer surface of the magnetic layer is treated with an oxygen-containing plasma; the overcoat layer is then applied to the treated outer surface.
- the oxygen-containing plasma is typically a mixture of oxygen and argon, although other oxygen-containing mixtures could be used as well. It is believed that the treatment creates a very thin layer of cobalt oxide at the outer surface of the magnetic layer.
- the cobalt oxide is believed to prevent carbon in the overcoat layer from diffusing into the magnetic layer. This results in improved magnetic properties and recording performance values.
- Fig. 1 is a simplified cross-sectional view of a prior art disk structure; and Fig. 2 is a cross-sectional view of a disk structure made according to the present invention.
- Fig. 2 illustrates a disk structure 2A made according to the invention.
- Disk structure 2A is same as the prior art disk structure 2 shown in Fig. 1 except that the outer surface 20 of magnetic layer 14 has been treated with an oxygen-containing plasma.
- the objectives of the treatment are to increase coercive squareness (S*) and remanence squareness (SQ) resulting in increasing the remanence (Mr). This process also improves the stability of magnetic properties and recording performance of disk during mass production.
- S* coercive squareness
- SQ remanence squareness
- Mr remanence squareness
- magnetic layer 14 was a sputtered layer of cobalt- containing material, specifically CoCrPtTa, about 35 ⁇ A thick.
- the product was placed in a plasma chamber and exposed to an oxygen- containing plasma, specifically about 65% argon and 35% oxygen.
- This treatment was carried out using a relatively small chamber with the ArO flow rate of about 16 seem; higher flow rates would typically be used in larger chambers.
- Sputtering time was about four seconds at a power of about .2 kW; the sputtering times and power can be varied according to the particular circumstances.
- carbon-containing overcoat layer 16 was sputtered on to surface 20.
- overcoat layer 16 included nitrogenic carbon; hydrogenic carbon could also be used instead of nitrogenic carbon. Carbon-containing overcoat layer 16 could also be made using, for example, CVD instead of sputtering. A lubricant layer 18 of Zdol was then applied to overcoat layer 16 by dip coating.
- Conventional disk structure 2 was manufactured in the same way as disk structure 2A, but without the treatment of surface 20. The magnetic properties and recording performance values of conventional disk structure 2 and treated disk structure 2A were measured using an Intevac MDP250 System. Results of these tests are as follows:
- SMNR is 20 log of the ratio of signal at high frequency ⁇ integrated noise
- PW50 is pulse width at half amplitude
- LF TAA low frequency track amplitude
- disk 2A with the surface treatment improves S*, SQ, SMNR, PW50 and LF TAA significantly.
- the coercive squareness (S*)of disk structure 2 varies between about 0.7-0.82.
- coercive squareness of disk structure 2 A is very good, varying from about .82 to .91.
- the magnetic properties and recording performance values, in particular coercive squareness are consistent during mass production.
- the present invention has been discussed with reference to an oxygen- containing plasma for the surface treatment. It is believed that the oxygen can be provided by O 2 or in other manners, such H 2 O. Also, although it is presently preferred to use a mixture of argon and oxygen, it is expected that one or more of the "inert gases,” specifically helium, neon, krypton, and xenon, can be used in lieu of argon.
- the flow rate of the mixture of gases was about 16 seem; it is believed that flow rates of the gases to be ionized could vary widely, such as from about 1 seem to about 1000 seem. It is expected that the argon-oxygen mixture could range from about 15% oxygen up to about 100% oxygen; however, the higher oxygen precentages may not be practical due to safety concerns.
- Magnetic layer 14 could be made of other cobalt-containing material and could be thicker or thinner than the 35 ⁇ A of the example.
- ZdolTM made by Ausimont USA, Inc. of Thorofare, N.J., is a PFPE disk lubricant having hydroxyl groups at both ends; other lubricants could be used as well.
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Manufacturing Of Magnetic Record Carriers (AREA)
Abstract
A magnetic recording medium includes a substrate (4), an overcoat layer (16) and a magnetic layer (14) therebetween. The magnetic layer contains cobalt and the overcoat layer contains carbon, as is conventional. The outer surface (20) of the magnetic layer is treated with an oxygen-containing plasma; the overcoat layer is then applied to the treated outer surface. The oxygen-containing plasma is typically a mixture of oxygen and argon, although other oxygen-containing mixtures could be used as well. This surface treatment results in improved magnetic properties and recording performance values.
Description
MAGNETIC RECORDING MEDIUM WITH IMPROVED PERFORMANCE PROPERTIES AND METHODS
BACKGROUND OF THE INVENTION Magnetic recording media are constantly being improved to increase data density. Key features to achieving high linear density for magnetic recording media are high playback signal, narrow pulse width, high signal-to-media noise ratio and good overwrite. To meet these criteria, the magnetic media requires high coercivity (Hr), low remanence-thickness product (Mr*), high coercive squareness (S*), high remanence squareness (SQ) and thin magnetic layer.
In general, Hr and Mr* are specified by the customer of disk drive company. For a disk manufacturing company, it is a challenge to obtain media with high S* and SQ, thin magnetic layer, and meanwhile, to maintain high signal-to-media noise ratio and good overwrite. From mass production point of view, a stable process is required to make consistent products.
A conventional magnetic recording disk structure 2 is shown in Fig. 1. Structure 2 includes a substrate 4, a first seed layer 6 (optional), a second seed layer 8 (optional), an underlayer 10, a transition magnetic layer 12 (optional), a magnetic layer 14, an overcoat layer 16 and a lubricant layer 18. The composition of overcoat layer 16 is typically carbon doped with H or N or both. The composition of magnetic layer 14 is typically Co alloys such as CoCrTa, CoCrTaPt, CoCrTaPtB, CoCrTaPtNb, etc. The transition magnetic layer 12 is an optional layer which provides a better lattice match transition between underlayer 10 and magnetic layer 14. The composition of transition magnetic layer 12 is similar to that of magnetic layer 14. The composition of underlayer 10 typically can be NiP, Cr and Cr alloys such as CrV, CrTi, CrMo, etc. Seed layers 6,8 are also optional layers. NiAl and NiP can be used for second seed layer 8 and MgO can be used for first seed layer 6. The materials of substrate 4 can be aluminum-magnesium alloys with a plated NiP layer, glass, glass-ceramic, ceramic, carbon, silicon, aluminum- boron-carbide alloys, etc.
SUMMARY OF THE INVENTION The present invention is directed to a magnetic recording medium with improved performance properties and methods. The invention improves magnetic properties and recording performance values for high density magnetic media and helps to stabilize the magnetic properties and recording performance values of the products using the media.
The magnetic recording medium is of the type including a substrate, an overcoat layer and a magnetic layer therebetween. The magnetic layer preferably contains cobalt and the overcoat layer preferably contains carbon, as is conventional. The outer surface of the magnetic layer is treated with an oxygen-containing plasma; the overcoat layer is then applied to the treated outer surface. The oxygen-containing plasma is typically a mixture of oxygen and argon, although other oxygen-containing mixtures could be used as well. It is believed that the treatment creates a very thin layer of cobalt oxide at the outer surface of the magnetic layer. The cobalt oxide is believed to prevent carbon in the overcoat layer from diffusing into the magnetic layer. This results in improved magnetic properties and recording performance values.
Other features and advantages will appear from the following description, in which the preferred embodiment has been set forth in detail in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a simplified cross-sectional view of a prior art disk structure; and Fig. 2 is a cross-sectional view of a disk structure made according to the present invention.
DESCRIPTION OF THE SPECIFIC EMBODIMENTS Fig. 2 illustrates a disk structure 2A made according to the invention. Disk structure 2A is same as the prior art disk structure 2 shown in Fig. 1 except that the outer surface 20 of magnetic layer 14 has been treated with an oxygen-containing plasma. The objectives of the treatment are to increase coercive squareness (S*) and remanence squareness (SQ) resulting in increasing the remanence (Mr). This process also improves the stability of magnetic properties and recording performance of disk during mass production.
Example:
In this example magnetic layer 14 was a sputtered layer of cobalt- containing material, specifically CoCrPtTa, about 35θA thick. After sputtering magnetic layer 14, the product was placed in a plasma chamber and exposed to an oxygen- containing plasma, specifically about 65% argon and 35% oxygen. This treatment was carried out using a relatively small chamber with the ArO flow rate of about 16 seem; higher flow rates would typically be used in larger chambers. Sputtering time was about four seconds at a power of about .2 kW; the sputtering times and power can be varied according to the particular circumstances. Following the surface treatment of outer surface 20 with the oxygen-containing plasma, carbon-containing overcoat layer 16 was sputtered on to surface 20. Specifically, overcoat layer 16 included nitrogenic carbon; hydrogenic carbon could also be used instead of nitrogenic carbon. Carbon-containing overcoat layer 16 could also be made using, for example, CVD instead of sputtering. A lubricant layer 18 of Zdol was then applied to overcoat layer 16 by dip coating. Conventional disk structure 2 was manufactured in the same way as disk structure 2A, but without the treatment of surface 20. The magnetic properties and recording performance values of conventional disk structure 2 and treated disk structure 2A were measured using an Intevac MDP250 System. Results of these tests are as follows:
Where:
SMNR is 20 log of the ratio of signal at high frequency ÷ integrated noise,
OW (overwrite) 20 log of low frequency residual signal ÷ low frequency output signal,
PW50 is pulse width at half amplitude, and
LF TAA is low frequency track amplitude.
As can be seen, disk 2A with the surface treatment improves S*, SQ, SMNR, PW50 and LF TAA significantly.
Without using this process, the coercive squareness (S*)of disk structure 2 varies between about 0.7-0.82. With the process, coercive squareness of disk structure 2 A is very good, varying from about .82 to .91. With the present invention, the magnetic properties and recording performance values, in particular coercive squareness, are consistent during mass production.
The present invention has been discussed with reference to an oxygen- containing plasma for the surface treatment. It is believed that the oxygen can be provided by O2 or in other manners, such H2O. Also, although it is presently preferred to use a mixture of argon and oxygen, it is expected that one or more of the "inert gases," specifically helium, neon, krypton, and xenon, can be used in lieu of argon.
In the Example, the flow rate of the mixture of gases was about 16 seem; it is believed that flow rates of the gases to be ionized could vary widely, such as from about 1 seem to about 1000 seem. It is expected that the argon-oxygen mixture could range from about 15% oxygen up to about 100% oxygen; however, the higher oxygen precentages may not be practical due to safety concerns. Magnetic layer 14 could be made of other cobalt-containing material and could be thicker or thinner than the 35θA of the example. Zdol™ made by Ausimont USA, Inc. of Thorofare, N.J., is a PFPE disk lubricant having hydroxyl groups at both ends; other lubricants could be used as well.
Modification and variation can be made to the disclosed embodiment without departing from the subject of the invention as defined in the following claims.
Claims
1. A method for improving performance properties of a magnetic recording medium comprising: forming a magnetic layer over a substrate for a magnetic recording medium, the magnetic layer having an outer surface; subjecting the outer surface of the magnetic layer to an oxygen-containing plasma; and applying an overcoat layer to the outer surface of the magnetic layer after the plasma subjecting step.
2. The method according to claim 1 wherein the forming step is carried out with the magnetic layer formed on an underlayer, the underlayer being between the magnetic layer and the substrate.
3. The method according to claim 1 wherein the forming step is carried out with the composition of the magnetic layer including cobalt.
4. The method according to claim 1 wherein the applying step is carried out with the composition of the overcoat layer including carbon.
5. The method according to claim 1 wherein the subjecting step is carried out using a mixture of oxygen and at least one of the following: argon, helium, neon, krypton, xenon.
6. The method according to claim 1 wherein the subjecting step is carried out with water vapor providing oxygen for the oxygen-containing plasma.
7. A magnetic recording medium made according to the method of claim 1.
8. A method for improving performance properties of a magnetic recording medium comprising: forming a cobalt-containing magnetic layer over a substrate for a magnetic recording medium, the magnetic layer having an outer surface; subjecting the outer surface of the magnetic layer to a plasma-containing mixture of oxygen and at least argon; and applying a carbon-containing overcoat layer to the outer surface of the magnetic layer after the plasma subjecting step.
9. A magnetic recording medium comprising: a substrate; a magnetic layer over the substrate, the magnetic layer having an outer surface facing away from the substrate; the outer surface of the magnetic layer comprising an oxygen-containing- plasma-treated outer surface; and an overcoat layer on the oxygen-containing-plasma-treated outer surface.
10. The magnetic recording medium according to claim 9 wherein the magnetic layer includes cobalt and the overcoat layer includes carbon.
1 1. The magnetic recording medium according to claim 10 wherein the oxygen-containing-plasma-treated outer surface includes cobalt oxide.
12. The magnetic recording medium according to claim 9 wherein the magnetic recording medium exhibits improved magnetic properties and recording performance values over a like magnetic recording medium but without said oxygen- containing-plasma-treated outer surface.
13. The magnetic recording medium according to claim 12 wherein said improved magnetic properties comprise at least one of S* and SQ and said improved recording performance values comprise at least one of SMNR, PW50 and LF TAA.
14. A magnetic recording medium comprising: a substrate; a cobalt-containing magnetic layer over the substrate, the magnetic layer having an outer surface facing away from the substrate; the outer surface of the magnetic layer comprising an oxygen-containing- plasma-treated outer surface; and a carbon-containing overcoat layer on the oxygen-containing-plasma- treated outer surface; wherein the magnetic recording medium exhibits improved magnetic properties and recording performance values over a like magnetic recording medium but without said oxygen-containing-plasma-treated outer surface, said improved magnetic properties comprising at least one of S* and SQ and said improved recording performance values comprising at least one of SMNR, PW50 and LF TAA.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU35964/00A AU3596400A (en) | 1999-02-16 | 2000-02-15 | Magnetic recording medium with improved performance properties and methods |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US25042799A | 1999-02-16 | 1999-02-16 | |
| US09/250,427 | 1999-02-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2000049608A1 true WO2000049608A1 (en) | 2000-08-24 |
Family
ID=22947704
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/US2000/003894 WO2000049608A1 (en) | 1999-02-16 | 2000-02-15 | Magnetic recording medium with improved performance properties and methods |
Country Status (2)
| Country | Link |
|---|---|
| AU (1) | AU3596400A (en) |
| WO (1) | WO2000049608A1 (en) |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4495242A (en) * | 1981-04-02 | 1985-01-22 | Fuji Photo Film Co., Ltd. | Magnetic recording medium |
| JPS60251519A (en) * | 1984-05-28 | 1985-12-12 | Hitachi Maxell Ltd | Magnetic recording medium |
| US4770924A (en) * | 1986-07-02 | 1988-09-13 | Tdk Corporation | Magnetic recording medium |
| JPH01271915A (en) * | 1988-04-22 | 1989-10-31 | Seiko Epson Corp | Magnetic storage body and magnetic storage device and its manufacture |
| JPH01271908A (en) * | 1988-04-22 | 1989-10-31 | Seiko Epson Corp | Magnetic storage body and magnetic storage device and its manufacture |
| US4880687A (en) * | 1986-05-09 | 1989-11-14 | Tdk Corporation | Magnetic recording medium |
| US4889767A (en) * | 1986-04-23 | 1989-12-26 | Tdk Corporation | Magnetic recording medium |
| EP0399848A2 (en) * | 1989-05-25 | 1990-11-28 | Hitachi Maxell Ltd. | Magnetic recording medium and method of manufacturing the same |
| EP0438212A1 (en) * | 1990-01-16 | 1991-07-24 | International Business Machines Corporation | High coercivity low noise cobalt alloy magnetic recording medium and its manufacturing process |
| US5059468A (en) * | 1986-03-29 | 1991-10-22 | Canon Kabushiki Kaisha | Magnetic recording medium |
-
2000
- 2000-02-15 AU AU35964/00A patent/AU3596400A/en not_active Abandoned
- 2000-02-15 WO PCT/US2000/003894 patent/WO2000049608A1/en active Application Filing
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4495242A (en) * | 1981-04-02 | 1985-01-22 | Fuji Photo Film Co., Ltd. | Magnetic recording medium |
| JPS60251519A (en) * | 1984-05-28 | 1985-12-12 | Hitachi Maxell Ltd | Magnetic recording medium |
| US5059468A (en) * | 1986-03-29 | 1991-10-22 | Canon Kabushiki Kaisha | Magnetic recording medium |
| US4889767A (en) * | 1986-04-23 | 1989-12-26 | Tdk Corporation | Magnetic recording medium |
| US4880687A (en) * | 1986-05-09 | 1989-11-14 | Tdk Corporation | Magnetic recording medium |
| US4770924A (en) * | 1986-07-02 | 1988-09-13 | Tdk Corporation | Magnetic recording medium |
| JPH01271915A (en) * | 1988-04-22 | 1989-10-31 | Seiko Epson Corp | Magnetic storage body and magnetic storage device and its manufacture |
| JPH01271908A (en) * | 1988-04-22 | 1989-10-31 | Seiko Epson Corp | Magnetic storage body and magnetic storage device and its manufacture |
| EP0399848A2 (en) * | 1989-05-25 | 1990-11-28 | Hitachi Maxell Ltd. | Magnetic recording medium and method of manufacturing the same |
| EP0438212A1 (en) * | 1990-01-16 | 1991-07-24 | International Business Machines Corporation | High coercivity low noise cobalt alloy magnetic recording medium and its manufacturing process |
Non-Patent Citations (3)
| Title |
|---|
| DATABASE WPI Section Ch Week 198949, Derwent World Patents Index; Class E12, AN 1989-361259, XP002138818 * |
| PATENT ABSTRACTS OF JAPAN vol. 010, no. 124 (P - 454) 9 May 1986 (1986-05-09) * |
| PATENT ABSTRACTS OF JAPAN vol. 014, no. 035 (P - 994) 23 January 1990 (1990-01-23) * |
Also Published As
| Publication number | Publication date |
|---|---|
| AU3596400A (en) | 2000-09-04 |
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