JP2007164836A - Magnetic recording medium and magnetic recording device - Google Patents

Magnetic recording medium and magnetic recording device Download PDF

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JP2007164836A
JP2007164836A JP2005356384A JP2005356384A JP2007164836A JP 2007164836 A JP2007164836 A JP 2007164836A JP 2005356384 A JP2005356384 A JP 2005356384A JP 2005356384 A JP2005356384 A JP 2005356384A JP 2007164836 A JP2007164836 A JP 2007164836A
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magnetic recording
recording medium
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Tetsunori Kanda
哲典 神田
Akira Yano
亮 矢野
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Maxell Holdings Ltd
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Hitachi Maxell Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording medium which has high magnetostatic characteristics and superior recording/reproduction characteristics, and a magnetic recording device equipped with the same. <P>SOLUTION: The magnetic recording medium has, on a nonmagnetic substrate 1, a soft magnetic backing layer 6 formed of a soft magnetic material, an undercoat layer 3 made of Al or alloy consisting principally of Al, a recording layer 4 formed of a laminated film formed by laminating a layer consisting principally of Co and a layer consisting principally of Pd alternately, and a protective layer 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は情報の記録再生を行うための情報記録再生装置に関し、特に高密度磁気記録に適した磁気記録媒体及び磁気記録装置に関する。   The present invention relates to an information recording / reproducing apparatus for recording / reproducing information, and more particularly to a magnetic recording medium and a magnetic recording apparatus suitable for high-density magnetic recording.

情報化社会の発展には目覚しいものがあり、文字情報のみならず音声及び画像情報を高速に処理することができる装置の１つとして、コンピュータ等に装着されている磁気記録方式の情報記録装置が知られている。現在は、この磁気記録方式の情報記録装置の記録密度を向上させつつ、装置を小型化する方向に開発が進められている。典型的な磁気記録装置は、複数の磁気記録媒体をスピンドル上に回転可能に装着している。各磁気記録媒体は、基板とその上に形成された磁性膜からなり、情報の記録は、特定の磁化方向を有する磁区を磁性膜中に形成することにより行われる。従来、記録される磁化の方向は、磁性膜面内であり、面内磁気記録方式と呼ばれている。面内磁気記録方式の磁気記録装置の高密度記録化は、磁性膜の膜厚を薄くし、構成する磁性結晶粒の粒径を微小化させ、且つ、各粒子間の磁気的相互作用を低減させることで達成してきた。しかし、結晶粒の微小化と各粒子間の磁気的相互作用の低減は、記録されたビットを構成する磁化の熱安定性を低下させることが問題となっている。この問題を緩和するために提案されているのが、垂直磁気記録方式で、これは、記録される磁化の方向を、基板に対して垂直方向にする。その結果、隣接ビット間は静磁気的に安定で、且つ、記録遷移領域は鋭くなる。さらに記録層と基板の間に軟磁性材料で構成された層（軟磁性裏打ち層）を加えることで、記録時の磁場を急峻にすることができるので、高い磁気異方性をもつ材料への記録が可能になり、磁化の熱安定性が向上するので、より高密度の記録が可能になる。   There is a remarkable development in the information society, and as one of the devices that can process not only character information but also voice and image information at high speed, there is a magnetic recording type information recording device attached to a computer or the like. Are known. Currently, development is progressing in the direction of downsizing the apparatus while improving the recording density of the information recording apparatus of this magnetic recording system. A typical magnetic recording apparatus has a plurality of magnetic recording media rotatably mounted on a spindle. Each magnetic recording medium includes a substrate and a magnetic film formed thereon, and information recording is performed by forming a magnetic domain having a specific magnetization direction in the magnetic film. Conventionally, the direction of magnetization recorded is in the plane of the magnetic film, which is called the in-plane magnetic recording method. High-density recording of the in-plane magnetic recording system magnetic recording device reduces the thickness of the magnetic film, reduces the size of the magnetic crystal grains, and reduces the magnetic interaction between the particles. Has been achieved. However, miniaturization of crystal grains and reduction of the magnetic interaction between the grains are problematic in that the thermal stability of magnetization constituting the recorded bit is lowered. In order to alleviate this problem, a perpendicular magnetic recording method has been proposed, which makes the direction of recorded magnetization perpendicular to the substrate. As a result, the adjacent bits are magnetostatically stable and the recording transition area becomes sharp. Furthermore, by adding a layer made of a soft magnetic material (soft magnetic backing layer) between the recording layer and the substrate, the magnetic field at the time of recording can be sharpened. Recording becomes possible and the thermal stability of magnetization is improved, so that higher density recording is possible.

上述の面内磁気記録方式の磁気記録媒体にはＣｏＰｔＣｒ基合金（以降、ＣｏＰｔＣｒ基合金媒体と称す）が使用されており、垂直磁気記録方式の磁気記録媒体としても同じＣｏＰｔＣｒ基合金媒体が主に研究されてきた。ＣｏＰｔＣｒ基合金の場合、磁気異方性はＣｏの結晶構造に起因する結晶磁気異方性に依る。Ｐｔは磁気異方性を高める為に添加され、Ｃｒは媒体の組織制御を行うために添加されている。   A CoPtCr-based alloy (hereinafter referred to as a CoPtCr-based alloy medium) is used for the above-described in-plane magnetic recording type magnetic recording medium, and the same CoPtCr-based alloy medium is mainly used as a perpendicular magnetic recording type magnetic recording medium. Have been studied. In the case of a CoPtCr-based alloy, the magnetic anisotropy depends on the magnetocrystalline anisotropy due to the Co crystal structure. Pt is added to increase the magnetic anisotropy, and Cr is added to control the structure of the medium.

しかしながら、高い記録密度を実現するためには磁化の熱安定性をさらに高める必要があり、ＣｏＰｔＣｒ基合金よりも高い磁気異方性を持つ材料を媒体に適用する必要がある。このような材料の一つとして、Ｃｏを主成分とする層とＰｄを主成分とする層を交互に積層したＣｏ／Ｐｄ多層膜がある。
H.Takahashi et.al, Journal of Magnetism and Magnetic Materials, vol.126, pp.282-284, 1993 However, in order to realize a high recording density, it is necessary to further increase the thermal stability of magnetization, and it is necessary to apply a material having a higher magnetic anisotropy than the CoPtCr-based alloy to the medium. As one of such materials, there is a Co / Pd multilayer film in which layers containing Co as a main component and layers containing Pd as a main component are alternately stacked.
H. Takahashi et.al, Journal of Magnetism and Magnetic Materials, vol.126, pp.282-284, 1993

Ｃｏ／Ｐｄ多層膜は、Ｃｏを主成分とする層及びＰｄを主成分とする層の膜厚や積層周期を変えることで、その磁気異方性エネルギーが構造によって大きく変化することが知られている。一方、多層膜の下地層としてＰｄが一般的に用いられている。しかし、下地膜は多層膜の構造に影響を与えるので、下地膜を改善することによっても磁気異方性が変化し、従来よりも高い磁気異方性エネルギーを得られる可能性がある。   A Co / Pd multilayer film is known to change its magnetic anisotropy energy greatly depending on the structure by changing the film thickness and stacking period of a layer mainly composed of Co and a layer mainly composed of Pd. Yes. On the other hand, Pd is generally used as an underlayer of the multilayer film. However, since the base film affects the structure of the multilayer film, the magnetic anisotropy changes even if the base film is improved, and there is a possibility that higher magnetic anisotropy energy can be obtained.

本発明の目的は、高い磁気異方性エネルギーを有して記録ビットの熱安定性が向上し、高密度磁気記録に適した磁気記録媒体及びそれを装着した磁気記録装置を提供することを目的とする。   An object of the present invention is to provide a magnetic recording medium having high magnetic anisotropy energy and improved thermal stability of a recording bit and suitable for high-density magnetic recording, and a magnetic recording apparatus equipped with the magnetic recording medium. And

本発明の第１の様態は、記録層がＣｏを主成分とする層とＰｄを主成分とする層を交互に積層した磁性材料からなり、残留磁化が膜面内方向より膜面に対して垂直方向の方が大きい垂直磁気記録方式あるいは熱アシスト磁気記録方式の記録媒体において、下地層をＡｌあるいはＡｌを主成分とする合金により形成した磁気特性及び記録特性に優れた新規な磁気記録媒体を提供する。   In the first aspect of the present invention, the recording layer is made of a magnetic material in which a layer containing Co as a main component and a layer containing Pd as a main component are alternately stacked, and the residual magnetization is directed to the film surface from the in-plane direction. In a perpendicular magnetic recording system or a thermally assisted magnetic recording system, which has a larger vertical direction, a new magnetic recording medium excellent in magnetic characteristics and recording characteristics in which an underlayer is formed of Al or an alloy containing Al as a main component. provide.

我々は、Ｃｏ／Ｐｄ多層膜の磁気異方性エネルギーを高めるべく検討した結果、ＡｌあるいはＡｌを主成分とする合金で形成される下地層上にＣｏ／Ｐｄ多層膜を具備する新規構造にすることで磁気異方性エネルギーが向上し、静磁気特性及び記録再生特性が改善されることを見出した。ＣｏとＰｄは非常に相性がよく、合金を作り易い組合せであり、多層膜中のＣｏとＰｄの界面ではＣｏＰｄ合金が形成し易いことが知られている。ＣｏＰｄ合金の磁歪定数の組成依存性については、非特許文献１に示されている。ここで重要なことは、ＣｏＰｄ合金の[１１１]方向は大きな負の磁歪定数を示すことであり、[１１１]方向に引っ張ると引っ張った方向と垂直方向に磁化が向き易くなる。   As a result of studying to increase the magnetic anisotropy energy of the Co / Pd multilayer film, we have a new structure including a Co / Pd multilayer film on an underlayer formed of Al or an alloy containing Al as a main component. As a result, it has been found that the magnetic anisotropy energy is improved and the magnetostatic characteristics and recording / reproducing characteristics are improved. It is known that Co and Pd have a very good compatibility and are easy to make an alloy, and a CoPd alloy is easily formed at the interface between Co and Pd in the multilayer film. The composition dependence of the magnetostriction constant of the CoPd alloy is shown in Non-Patent Document 1. What is important here is that the [111] direction of the CoPd alloy exhibits a large negative magnetostriction constant, and when pulled in the [111] direction, the magnetization is likely to be oriented in the direction perpendicular to the pulled direction.

下地層に用いられるＡｌ及びＡｌ合金はＣｏ／Ｐｄ多層膜よりも格子定数が大きい。さらに、結晶構造はＡｌ、Ａｌ合金とＣｏ／Ｐｄ多層膜は共に面心立方構造である。面心立方構造の薄膜は、最密充填面の（１１１）面が優先配向する。従って、Ａｌ下地膜あるいはＡｌを主成分とする合金下地膜上にＣｏ／Ｐｄ多層膜を形成した場合、Ｃｏ／Ｐｄ多層膜は下地膜上にエピタキシャル成長し、下地層との格子定数の差に起因して、引張り応力を受けることになる。この引張り方向は［１１１］なので、垂直磁気異方性エネルギーが従来のＣｏ／Ｐｄ多層膜よりも向上すると考えられる。   Al and Al alloy used for the underlayer have a larger lattice constant than the Co / Pd multilayer film. Further, the crystal structure is Al, Al alloy and the Co / Pd multilayer film are both face centered cubic structures. In a thin film having a face-centered cubic structure, the (111) plane of the closest packing surface is preferentially oriented. Therefore, when a Co / Pd multilayer film is formed on an Al base film or an alloy base film containing Al as a main component, the Co / Pd multilayer film is epitaxially grown on the base film, resulting from a difference in lattice constant from the base layer. Therefore, it will receive a tensile stress. Since the tensile direction is [111], it is considered that the perpendicular magnetic anisotropy energy is improved as compared with the conventional Co / Pd multilayer film.

本発明の磁気記録媒体では、下地層の下に軟磁性裏打ち層を設けても良い。軟磁性裏打ち層は、主磁極と補助磁極を有する単磁極型の磁気ヘッドを用いて記録層に情報を記録するときに、磁気ヘッドから漏れ出した磁束を記録層に集束させる役割を持つ。軟磁性裏打ち層の材料としては、飽和磁化が大きく、保磁力が小さく、且つ、透磁率が高い軟磁性材料が好ましく、それに対応する材料として、例えば、ＣｏＴａＺｒ膜などがある。また、この軟磁性裏打ち層の膜厚は、２５〜５００ｎｍの範囲であることが望ましい。   In the magnetic recording medium of the present invention, a soft magnetic backing layer may be provided under the underlayer. The soft magnetic backing layer has a role of concentrating the magnetic flux leaking from the magnetic head on the recording layer when information is recorded on the recording layer using a single magnetic pole type magnetic head having a main magnetic pole and an auxiliary magnetic pole. As a material for the soft magnetic underlayer, a soft magnetic material having a large saturation magnetization, a small coercive force, and a high magnetic permeability is preferable, and a material corresponding thereto is, for example, a CoTaZr film. The film thickness of the soft magnetic backing layer is preferably in the range of 25 to 500 nm.

本発明の第２の様態に従えば、軟磁性裏打ち層を有する本発明の磁気記録媒体を用い、記録層の膜面に対して垂直方向の磁化を与え、かつ、軟磁性裏打ち層の膜面に対して平行方向の磁化を与え、記録層と軟磁性裏打ち層と協同して磁気回路を形成する磁気ヘッドと、磁気記録媒体を磁気ヘッドに対して相対的に駆動するための駆動装置とを備えた垂直磁気記録方式の情報記録装置が提供される。   According to the second aspect of the present invention, the magnetic recording medium of the present invention having a soft magnetic underlayer is used, magnetization in the direction perpendicular to the film surface of the recording layer is given, and the film surface of the soft magnetic underlayer A magnetic head that forms a magnetic circuit in cooperation with the recording layer and the soft magnetic underlayer, and a drive device for driving the magnetic recording medium relative to the magnetic head. An perpendicular magnetic recording type information recording apparatus is provided.

また、このような高い垂直磁気異方性エネルギーを有する記録媒体の場合、前述のように保磁力が高くなるため、記録ヘッドで形成する磁場では十分な記録ができない場合がある。高保磁力の媒体に磁気記録を行う手法として、記録時にレーザで媒体を照射して高温にすることで媒体の保磁力を低減させて記録する熱アシスト磁気記録方式がある。昇温して記録する方式の場合に考慮すべきは、レーザ照射時の熱を効率良く逃がす膜構造とすることである。これは、記録時の高温状態からできるだけ速く磁気的に安定な温度にまで下げることが重要だからである。この点、Ａｌは熱伝導率の高い材料であり、ＡｌあるいはＡｌを主成分とする合金は、熱アシスト磁気記録方式の記録層の下地層として効果的である。ＡｌあるいはＡｌを主成分とする合金をＣｏ／Ｐｄ多層膜の下地膜として用いることで、高い磁気異方性を発現し、且つ、熱アシスト磁気記録に適した媒体構造を得ることができる。   Further, in the case of a recording medium having such a high perpendicular magnetic anisotropy energy, the coercive force is increased as described above, and therefore, sufficient recording may not be possible with a magnetic field formed by a recording head. As a technique for performing magnetic recording on a medium having a high coercive force, there is a heat-assisted magnetic recording method in which recording is performed by reducing the coercive force of the medium by irradiating the medium with a laser at a high temperature during recording. In the case of a system in which the temperature is raised and recorded, a film structure that efficiently releases heat during laser irradiation should be considered. This is because it is important to reduce from a high temperature state during recording to a magnetically stable temperature as quickly as possible. In this respect, Al is a material having a high thermal conductivity, and Al or an alloy containing Al as a main component is effective as an underlayer for the recording layer of the heat-assisted magnetic recording method. By using Al or an alloy containing Al as a main component as the base film of the Co / Pd multilayer film, a medium structure that exhibits high magnetic anisotropy and is suitable for heat-assisted magnetic recording can be obtained.

つまり、本発明の第３の様態に従えば、軟磁性裏打ち層を備える本発明の磁気記録媒体を用い、加熱機構により媒体を加熱しながら記録層の膜面に対して垂直方向の磁化を与え、かつ、軟磁性裏打ち層の膜面に対して平行方向の磁化を与え、記録層と軟磁性裏打ち層と協同して磁気回路を形成する磁気ヘッドと、磁気記録媒体を磁気ヘッドに対して相対的に駆動するための駆動装置とを備えた熱アシスト磁気記録方式の磁気記録装置が提供される。   That is, according to the third aspect of the present invention, the magnetic recording medium of the present invention having a soft magnetic underlayer is used, and magnetization is applied in a direction perpendicular to the film surface of the recording layer while heating the medium by a heating mechanism. And a magnetic head that applies a magnetization in a direction parallel to the film surface of the soft magnetic underlayer and forms a magnetic circuit in cooperation with the recording layer and the soft magnetic underlayer, and a magnetic recording medium relative to the magnetic head. There is provided a magnetic recording apparatus of a thermally assisted magnetic recording system provided with a driving apparatus for driving in an automatic manner.

下地層のＡｌ合金に用いる元素としては、Ｐｔ，Ｐｄ，Ｔｉ，Ａｕ，Ｗ，Ｔａ，Ｒｅ，Ｏｓ，Ｉｒのうちの少なくとも１種の元素が望ましい。これらの元素は原子半径が大きいので、Ａｌと合金を形成した場合も充分に磁気特性を向上させることが可能である。   As an element used for the Al alloy of the underlayer, at least one element of Pt, Pd, Ti, Au, W, Ta, Re, Os, and Ir is desirable. Since these elements have a large atomic radius, it is possible to sufficiently improve the magnetic characteristics even when an alloy is formed with Al.

本発明によれば、ＡｌあるいはＡｌを主成分とする合金下地層、及びＣｏとＰｄを交互に積層した磁性層を備えることにより、高い磁気特性と優れた記録特性を両立する高密度記録可能な磁気記録媒体を提供することができる。   According to the present invention, Al or an alloy base layer containing Al as a main component and a magnetic layer in which Co and Pd are alternately laminated are provided so that high-density recording capable of achieving both high magnetic characteristics and excellent recording characteristics is possible. A magnetic recording medium can be provided.

以下に、本発明の磁気記録媒体及び磁気記録装置について実施例を用いて具体的に説明する。ただし、本発明は以下の実施例に限定されない。
（実施例１）
実施例１で作製した磁気記録媒体の概略断面図を図１に示す。図１に示すように、この磁気記録媒体１０は、基板１上に、密着層２、下地層３、記録層４、及び保護層５を順次積層した構造を有する。密着層２は、基板１とその上に積層された膜との剥離を防ぐための層である。下地層３は、記録層４の磁気特性を向上させるための層である。記録層４は、情報が磁化情報として記録される層であり、その磁化方向は膜面に対して垂直方向となる。保護層５は、基板１上に順次積層された積層膜２〜４を保護するための層である。以下に、この例で作製した情報記録媒体の作製方法を説明する。 Hereinafter, the magnetic recording medium and the magnetic recording apparatus of the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples.
Example 1
A schematic cross-sectional view of the magnetic recording medium manufactured in Example 1 is shown in FIG. As shown in FIG. 1, the magnetic recording medium 10 has a structure in which an adhesion layer 2, an underlayer 3, a recording layer 4, and a protective layer 5 are sequentially laminated on a substrate 1. The adhesion layer 2 is a layer for preventing peeling between the substrate 1 and a film laminated thereon. The underlayer 3 is a layer for improving the magnetic characteristics of the recording layer 4. The recording layer 4 is a layer in which information is recorded as magnetization information, and the magnetization direction is perpendicular to the film surface. The protective layer 5 is a layer for protecting the laminated films 2 to 4 sequentially laminated on the substrate 1. A method for manufacturing the information recording medium manufactured in this example will be described below.

基板１には直径２．５インチ（６．５ｃｍ）の円板状のガラス基板を用いた。その基板１上に、密着層２としてＴｉ膜を、ＤＣスパッタリングにより形成した。スパッタリング条件は、ガス圧０．２８Ｐａ、投入電力５００Ｗとし、ターゲットはＴｉとした。密着層２の膜厚は５ｎｍとした。   As the substrate 1, a disc-shaped glass substrate having a diameter of 2.5 inches (6.5 cm) was used. A Ti film as an adhesion layer 2 was formed on the substrate 1 by DC sputtering. The sputtering conditions were a gas pressure of 0.28 Pa, an input power of 500 W, and a target of Ti. The film thickness of the adhesion layer 2 was 5 nm.

次に、密着層２上に、下地層３としてＡｌ膜をＤＣスパッタリングにより形成した。スパッタリング条件は、ガス圧０．５Ｐａ、投入電力２００Ｗとし、Ａｌターゲットを用いた。下地層３の膜厚は１０ｎｍとした。   Next, an Al film was formed as a base layer 3 on the adhesion layer 2 by DC sputtering. The sputtering conditions were a gas pressure of 0.5 Pa, an input power of 200 W, and an Al target was used. The film thickness of the underlayer 3 was 10 nm.

次に、下地層３上に、記録層４としてＣｏ／Ｐｄ多層膜磁性膜を形成した。多層膜は、Ａｒガスを用いて、ＤＣマグネトロンスパッタ法でＰｄターゲット、Ｃｏターゲットを放電し、各ターゲット上についたシャッターを開閉することによって、０．２ｎｍ厚のＣｏと０．７ｎｍ厚のＰｄを交互に下地層４上に積層する方法で形成した。積層数は各２０層とした。スパッタリング条件は、ガス圧０．８Ｐａ、Ｃｏターゲット、Ｐｄターゲット共に投入電力１００Ｗとした。   Next, a Co / Pd multilayer magnetic film was formed as the recording layer 4 on the underlayer 3. The multilayer film uses Ar gas to discharge Pd targets and Co targets by DC magnetron sputtering, and opens and closes a shutter on each target, so that 0.2 nm thick Co and 0.7 nm thick Pd are formed. It formed by the method of laminating | stacking on the base layer 4 by turns. The number of stacked layers was 20 layers each. The sputtering conditions were a gas pressure of 0.8 Pa, a Co target, and a Pd target with an input power of 100 W.

最後に、記録層４上に、保護層５としてアモルファスカーボン膜をＤＣスパッタリングにより形成した。スパッタリング条件は、ガス圧０．２０Ｐａ、投入電力３００Ｗとし、保護層５の膜厚は３ｎｍとした。   Finally, an amorphous carbon film was formed as a protective layer 5 on the recording layer 4 by DC sputtering. The sputtering conditions were such that the gas pressure was 0.20 Pa, the input power was 300 W, and the thickness of the protective layer 5 was 3 nm.

（比較例１）
比較例１の媒体は、下地層３としてＰｄを用いた。それ以外は実施例１と同様にして作製した。 (Comparative Example 1)
In the medium of Comparative Example 1, Pd was used as the underlayer 3. Other than that was produced in the same manner as in Example 1.

次に、実施例１、比較例１の媒体について、磁気異方性エネルギー定数を磁気トルク法により評価した。その結果を表１に示す。   Next, the magnetic anisotropy energy constant of the media of Example 1 and Comparative Example 1 was evaluated by the magnetic torque method. The results are shown in Table 1.

Figure 2007164836
Figure 2007164836

この磁気特性の違いを調べるため、実施例１と比較例１の試料のＸ線回折測定を行い、結晶性を評価した。記録層４と下地層３は、共に結晶構造が面心立方構造であるため最密充填面の（１１１）が優先配向することがわかったので、図２にはピークが検出された角度付近のみを示した。実施例１、比較例１の記録層４と下地層３のピーク位置からそれぞれの（１１１）面間隔を算出し、ミスフィット量を求めた。ここで、ミスフィット量は、記録層と下地層の（１１１）面間隔の差を記録層の（１１１）面間隔で割った値として定義した。ミスフィット量を記録層及び下地層の（１１１）面間隔の値と併せて表２に示す。   In order to investigate the difference in magnetic characteristics, X-ray diffraction measurement was performed on the samples of Example 1 and Comparative Example 1 to evaluate the crystallinity. Since both the recording layer 4 and the underlayer 3 have a face-centered cubic structure, it has been found that (111) of the closest packing surface is preferentially oriented, so FIG. 2 shows only the vicinity of the angle at which the peak is detected. showed that. The respective (111) plane spacings were calculated from the peak positions of the recording layer 4 and the underlayer 3 of Example 1 and Comparative Example 1, and the amount of misfit was obtained. Here, the misfit amount was defined as a value obtained by dividing the difference between the (111) plane spacings of the recording layer and the underlayer by the (111) plane spacing of the recording layer. The amount of misfit is shown in Table 2 together with the value of the (111) plane spacing of the recording layer and the underlayer.

Figure 2007164836
Figure 2007164836

記録層と下地層の面間隔を比較すると、下地層の面間隔の方が広がっているので、記録層には引張り応力がかかることになる。ミスフィット量は記録層と下地層の面間隔の差が大きくなるとともに大きくなる。従って、実施例１と比較例１を比べると、実施例１の方がより記録層に引張り応力が働いていることがわかる。この違いが、磁気異方性エネルギーの差になっていると考えている。   Comparing the surface spacing of the recording layer and the underlayer, the surface spacing of the underlayer is wider, so that a tensile stress is applied to the recording layer. The amount of misfit increases as the difference in surface spacing between the recording layer and the underlayer increases. Therefore, when Example 1 and Comparative Example 1 are compared, it can be seen that Example 1 exerts more tensile stress on the recording layer. This difference is considered to be a difference in magnetic anisotropy energy.

次に、実施例１及び比較例１の媒体の記録再生特性を評価した。記録再生特性を評価する際には、図３に示すように、下地層下部に軟磁性裏打ち層６としてＣｏＴａＺｒを１００ｎｍ形成した。軟磁性裏打ち層は記録磁場を強める効果があり、記録特性を向上させる。実施例１及び比較例１で作製した磁気記録媒体の保護層上に１ｎｍの厚さの潤滑剤を塗布した後、その磁気記録媒体を、図４に示した磁気記録装置６０内に装着して記録再生特性を評価した。   Next, the recording / reproduction characteristics of the media of Example 1 and Comparative Example 1 were evaluated. When evaluating the recording / reproducing characteristics, as shown in FIG. 3, CoTaZr was formed as a soft magnetic underlayer 6 to a thickness of 100 nm under the underlayer. The soft magnetic underlayer has the effect of increasing the recording magnetic field and improves the recording characteristics. After applying a lubricant having a thickness of 1 nm on the protective layer of the magnetic recording medium produced in Example 1 and Comparative Example 1, the magnetic recording medium was mounted in the magnetic recording apparatus 60 shown in FIG. The recording / reproduction characteristics were evaluated.

図４（ａ）は磁気記録装置の概略平面図であり、図４（ｂ）は磁気ヘッドの断面模式図である。情報記録媒体１０は回転駆動系のスピンドル５２により回転される。磁気ヘッド５３は記録ヘッドと再生ヘッドを備える。記録ヘッドは、主磁極と補助磁極を有する単磁極ヘッド５６と半導体レーザと開口部が一体化した光照射部５５を有する。半導体レーザは波長４０５ｎｍのレーザ光を発生するものであり、情報を記録する際には、レーザ光照射によって媒体を加熱することができる。単磁極ヘッド５６にはトレーリングシールドが付いており、トレーリングシールドギャップ長Ｇｔｓ＝３５ｎｍ、トラック幅Ｔｗ＝７０−１００ｎｍ、磁束密度２．４５Ｔである。再生ヘッドは、一対の磁気シールド５８の間に配置されたスピンバルブ型磁気抵抗効果素子５７（Ｔｗｒ＝６０ｎｍ、Ｇｓ＝５０ｎｍ、ＭＲ比＝１３％）を備え、再生ヘッド直下のビットからもれる磁束を検出することができる。単磁極ヘッド、光照射部及び再生ヘッドは一体化されている。この一体型磁気ヘッド５３は磁気ヘッド駆動系５４により制御される。情報記録装置６０の磁気ヘッド浮上面と情報記録媒体面との距離は５ｎｍに保った。   4A is a schematic plan view of the magnetic recording apparatus, and FIG. 4B is a schematic cross-sectional view of the magnetic head. The information recording medium 10 is rotated by a spindle 52 of a rotational drive system. The magnetic head 53 includes a recording head and a reproducing head. The recording head has a single magnetic pole head 56 having a main magnetic pole and an auxiliary magnetic pole, and a light irradiation part 55 in which a semiconductor laser and an opening are integrated. The semiconductor laser generates laser light having a wavelength of 405 nm, and when recording information, the medium can be heated by laser light irradiation. The single magnetic pole head 56 has a trailing shield, and the trailing shield gap length Gts = 35 nm, the track width Tw = 70-100 nm, and the magnetic flux density 2.45T. The reproducing head includes a spin valve magnetoresistive element 57 (Twr = 60 nm, Gs = 50 nm, MR ratio = 13%) disposed between a pair of magnetic shields 58, and a magnetic flux leaking from a bit immediately below the reproducing head. Can be detected. The single magnetic pole head, the light irradiation unit, and the reproducing head are integrated. This integrated magnetic head 53 is controlled by a magnetic head drive system 54. The distance between the magnetic head air bearing surface of the information recording device 60 and the information recording medium surface was kept at 5 nm.

この情報記録装置６０の磁気ヘッド５３により、情報記録媒体１０の記録層４の膜面に対して垂直方向の磁化を与え、かつ、軟磁性裏打ち層６の膜面に対して平行方向の磁化を与え、記録層及び軟磁性裏打ち層６と協同して磁気回路を構成することができる。   The magnetic head 53 of the information recording device 60 gives a magnetization in a direction perpendicular to the film surface of the recording layer 4 of the information recording medium 10 and a magnetization in a direction parallel to the film surface of the soft magnetic backing layer 6. The magnetic circuit can be constructed in cooperation with the recording layer and the soft magnetic backing layer 6.

この情報記録媒体１０を用いて、線記録密度２０ｋＦＣＩの信号を記録した際の再生出力（Ｓｌｆ）と、線記録密度１０００ｋＦＣＩでのノイズ（Ｎｄ）との比を情報記録媒体の記録再生特性（Ｓｌｆ／Ｎｄ比）として評価した。記録は、半導体レーザに１０ｍＷのパワーを印加して記録媒体を加熱しながら行った。表３にＳｌｆ／Ｎｄ比の測定結果を示す。   Using this information recording medium 10, the ratio of the reproduction output (Slf) when recording a signal with a linear recording density of 20 kFCI and the noise (Nd) at a linear recording density of 1000 kFCI is the recording / reproduction characteristic (Slf) of the information recording medium. / Nd ratio). Recording was performed while heating the recording medium by applying a power of 10 mW to the semiconductor laser. Table 3 shows the measurement results of the Slf / Nd ratio.

Figure 2007164836
Figure 2007164836

このように実施例１の媒体の方が記録再生特性が優れていることがわかる。この理由として、磁気異方性が向上して高記録密度のビットの安定性が高まっていること、実施例１では下地層に熱伝導性の高いＡｌを用いていることが効いていることが考えられる。以上より、実施例１のようにＡｌを下地層に用いる構造は、熱アシスト磁気記録方式として適した媒体構造であることがわかる。   Thus, it can be seen that the medium of Example 1 has better recording and reproduction characteristics. This is because the magnetic anisotropy is improved and the stability of the high recording density bit is increased, and in Example 1, the use of Al having high thermal conductivity for the underlayer is effective. Conceivable. From the above, it can be seen that the structure using Al as the underlayer as in Example 1 is a medium structure suitable for the heat-assisted magnetic recording system.

（実施例２）
実施例２では、実施例１と同様の膜構造で記録再生評価を行った。その際に、実施例１とは異なり、記録時の熱アシストは行わず室温で記録を行う通常の垂直磁気記録で行った。実施例１と同様に、線記録密度２０ｋＦＣＩの信号を記録した際の再生出力（Ｓｌｆ）とし、線記録密度１０００ｋＦＣＩでのノイズ（Ｎｄ）との比を磁気記録媒体の記録再生特性（Ｓｌｆ／Ｎｄ比）として評価した。表４にＳｌｆ／Ｎｄ比の測定結果を示す。表４には比較のために、比較例１の媒体に対しても、垂直磁気記録を行った場合の記録再生特性も併せて示した。 (Example 2)
In Example 2, the recording / reproduction evaluation was performed with the same film structure as in Example 1. At that time, unlike Example 1, normal perpendicular magnetic recording was performed in which recording was performed at room temperature without performing thermal assist during recording. As in Example 1, the reproduction output (Slf) when a signal with a linear recording density of 20 kFCI was recorded, and the ratio with the noise (Nd) at a linear recording density of 1000 kFCI was the recording / reproduction characteristics (Slf / Nd) of the magnetic recording medium. Ratio). Table 4 shows the measurement results of the Slf / Nd ratio. For comparison, Table 4 also shows recording / reproduction characteristics when perpendicular magnetic recording is performed on the medium of Comparative Example 1.

Figure 2007164836
Figure 2007164836

このように従来の垂直磁気記録方式でも、Ａｌ下地膜を用いた実施例２の方が従来のＰｄ下地層を用いた比較例１よりも優れた記録再生特性を示した。これは、磁気特性の差に起因すると考えられる。   Thus, even in the conventional perpendicular magnetic recording system, Example 2 using an Al underlayer showed better recording / reproducing characteristics than Comparative Example 1 using a conventional Pd underlayer. This is considered due to a difference in magnetic characteristics.

（実施例３）
実施例３では、Ａｌを主成分とした種々の合金材料を用いて下地層３を形成し、下地層の材料以外は実施例１の軟磁性裏打ち層６を有する媒体と同様の膜構造の媒体を作製した。表５に、作製した磁気記録媒体の下地層の材料、磁気特性及び線記録密度２０ｋＦＣＩの信号を記録した際の再生出力（Ｓｌｆ）と線記録密度１０００ｋＦＣＩでのノイズ（Ｎｄ）との比を磁気記録媒体の記録再生特性（Ｓｌｆ／Ｎｄ比）として評価した結果を示した。記録方式としては、レーザで媒体を加熱する熱アシスト磁気記録方式及びレーザ加熱を用いない垂直磁気記録方式双方の記録再生評価を行った。 (Example 3)
In Example 3, the base layer 3 is formed using various alloy materials mainly composed of Al, and a medium having the same film structure as the medium having the soft magnetic backing layer 6 of Example 1 except for the material of the base layer. Was made. Table 5 shows the ratio of the material of the underlayer of the produced magnetic recording medium, the magnetic characteristics, and the reproduction output (Slf) when recording a signal with a linear recording density of 20 kFCI to the noise (Nd) at a linear recording density of 1000 kFCI. The results of evaluation as recording / reproducing characteristics (Slf / Nd ratio) of the recording medium are shown. As a recording method, recording / reproduction evaluation was performed for both a heat-assisted magnetic recording method in which a medium is heated with a laser and a perpendicular magnetic recording method in which laser heating is not used.

Figure 2007164836
Figure 2007164836

表５から、Ａｌを主成分とする合金を下地膜としても、Ａｌを下地膜とした場合と同様の効果を得ることができることがわかる。   From Table 5, it can be seen that even when an alloy containing Al as a main component is used as the base film, the same effect as that obtained when Al is used as the base film can be obtained.

下地層の膜厚は５ｎｍ以上、２０ｎｍ以下であることが望ましい。下地膜が５ｎｍより薄いと結晶配向性が乱れるために磁気特性が劣化し、２０ｎｍを超える膜厚になると、記録ヘッドと軟磁性裏打ち層とのスペーシングを近づける方が記録特性が向上するからである。   The film thickness of the underlayer is desirably 5 nm or more and 20 nm or less. If the base film is thinner than 5 nm, the crystal orientation is disturbed and the magnetic characteristics deteriorate, and if the film thickness exceeds 20 nm, the closer the spacing between the recording head and the soft magnetic backing layer, the better the recording characteristics. is there.

上記実施例では、情報記録媒体の基板材料としてガラスを用いた例を説明したが、本発明はこれに限定されない。場合によっては、アルミニウム、ポリカーボネートなどのプラスチック、あるいは、樹脂等を用いても良い。   In the above-described embodiment, an example in which glass is used as the substrate material of the information recording medium has been described. However, the present invention is not limited to this. In some cases, a plastic such as aluminum or polycarbonate, or a resin may be used.

以上の実施例では、磁気記録媒体の軟磁性裏打ち層としてＣｏＴａＺｒ膜を設けた例を用いて説明したが、本発明はこれに限定されない。軟磁性裏打ち層としては、ＦｅＴａＣ、ＦｅＴａＮ、ＦｅＡｌＳｉ、ＦｅＣ、ＣｏＢ、ＣｏＴａＮｂ、ＮｉＦｅ、あるいは、それらの軟磁性膜とＣ膜の積層膜であっても良い。ただ、ＣｏＴａＺｒ膜は最も望ましい。   In the above embodiment, the example in which the CoTaZr film is provided as the soft magnetic backing layer of the magnetic recording medium has been described. However, the present invention is not limited to this. The soft magnetic backing layer may be FeTaC, FeTaN, FeAlSi, FeC, CoB, CoTaNb, NiFe, or a laminated film of these soft magnetic films and C films. However, the CoTaZr film is most desirable.

実施例1の磁気記録媒体の断面構造を示す模式図。FIG. 2 is a schematic diagram showing a cross-sectional structure of the magnetic recording medium of Example 1. 実施例１と比較例１の媒体のＸ線回折測定結果を示す図。The figure which shows the X-ray-diffraction measurement result of the medium of Example 1 and Comparative Example 1. 軟磁性裏打ち層を有する磁気記録媒体の断面構造を示す模式図。1 is a schematic diagram showing a cross-sectional structure of a magnetic recording medium having a soft magnetic underlayer. 本発明で作製した情報記録媒体を備えた情報記録装置の概略図であり、（ａ）は平面図、（ｂ）は断面模式図。It is the schematic of the information recording device provided with the information recording medium produced by this invention, (a) is a top view, (b) is a cross-sectional schematic diagram.

符号の説明Explanation of symbols

１ 基板
２ 密着層
３ 下地層
４ 記録層
５ 保護層
６ 軟磁性裏打ち層
１０ 情報記録媒体
６０ 情報記録装置
５２ スピンドル
５３ 磁気ヘッド
５４ 磁気ヘッド駆動系
５５ 光照射部
５６ 単磁極ヘッド
５７ 磁気抵抗効果素子
５８ 磁気シールド DESCRIPTION OF SYMBOLS 1 Substrate 2 Adhesion layer 3 Underlayer 4 Recording layer 5 Protective layer 6 Soft magnetic backing layer 10 Information recording medium 60 Information recording device 52 Spindle 53 Magnetic head 54 Magnetic head drive system 55 Light irradiation unit 56 Single pole head 57 Magnetoresistive element 58 Magnetic shield

Claims (6)

下地層と、前記下地層の上に形成された記録層とを備える垂直磁気記録方式の磁気記録媒体において、
前記下地層はＡｌあるいはＡｌを主成分とする合金からなり、前記記録層はＣｏを主成分とする層とＰｄを主成分とする層を交互に積層した積層膜であることを特徴とする磁気記録媒体。 In a perpendicular magnetic recording type magnetic recording medium comprising an underlayer and a recording layer formed on the underlayer,
The underlayer is made of Al or an alloy containing Al as a main component, and the recording layer is a laminated film in which layers containing Co as a main component and layers containing Pd as a main component are alternately laminated. recoding media. 下地層と、前記下地層の上に形成された記録層とを備える熱アシスト磁気記録方式の磁気記録媒体において、
前記下地層はＡｌあるいはＡｌを主成分とする合金からなり、前記記録層はＣｏを主成分とする層とＰｄを主成分とする層を交互に積層した積層膜であることを特徴とする磁気記録媒体。 In a thermally assisted magnetic recording magnetic recording medium comprising an underlayer and a recording layer formed on the underlayer,
The underlayer is made of Al or an alloy containing Al as a main component, and the recording layer is a laminated film in which layers containing Co as a main component and layers containing Pd as a main component are alternately laminated. recoding media. 請求項１又は２記載の磁気記録媒体において、前記下地層はＰｔ，Ｐｄ，Ｔｉ，Ａｕ，Ｗ，Ｔａ，Ｒｅ，Ｏｓ，Ｉｒの中から選ばれる少なくとも１種類の元素を含むＡｌ合金であることを特徴とする磁気記録媒体。   3. The magnetic recording medium according to claim 1, wherein the underlayer is an Al alloy containing at least one element selected from Pt, Pd, Ti, Au, W, Ta, Re, Os, and Ir. A magnetic recording medium characterized by the above. 請求項１〜３のいずれか１項記載の磁気記録媒体において、前記下地膜の下に軟磁性裏打ち層を有することを特徴とする磁気記録媒体。   4. The magnetic recording medium according to claim 1, further comprising a soft magnetic backing layer under the underlayer. 磁気記録媒体と、前記磁気記録媒体を駆動する媒体駆動部と、前記磁気記録媒体に対して記録動作を行う磁気ヘッドと、前記磁気ヘッドを前記磁気記録媒体に対して位置決めするためのヘッド駆動部とを有する磁気記録装置において、
前記磁気記録媒体は、ＡｌあるいはＡｌを主成分とする合金からなる下地層と、前記下地層の上に形成された、Ｃｏを主成分とする層とＰｄを主成分とする層を交互に積層した積層膜からなる記録層とを備えた垂直磁気記録方式の磁気記録媒体であることを特徴とする磁気記録装置。 A magnetic recording medium, a medium driving unit for driving the magnetic recording medium, a magnetic head for performing a recording operation on the magnetic recording medium, and a head driving unit for positioning the magnetic head with respect to the magnetic recording medium In a magnetic recording device having
The magnetic recording medium is formed by alternately laminating an underlayer made of Al or an alloy containing Al as a main component, and a layer containing Co as a main component and a layer containing Pd as a main component formed on the underlayer. What is claimed is: 1. A magnetic recording apparatus comprising: a perpendicular magnetic recording type magnetic recording medium comprising a recording layer comprising a laminated film. 磁気記録媒体と、前記磁気記録媒体を駆動する媒体駆動部と、前記磁気記録媒体に対して記録動作を行う磁気ヘッドと、前記磁気ヘッドを前記磁気記録媒体に対して位置決めするためのヘッド駆動部とを有する磁気記録装置において、
前記磁気記録媒体は、ＡｌあるいはＡｌを主成分とする合金からなる下地層と、前記下地層の上に形成された、Ｃｏを主成分とする層とＰｄを主成分とする層を交互に積層した積層膜からなる記録層とを備えた垂直磁気記録方式の磁気記録媒体であり、
前記磁気ヘッドは前記記録層を加熱する手段と、前記加熱された記録層の領域に垂直方向の磁化を与える磁極とを有することを特徴とする磁気記録装置。 A magnetic recording medium, a medium driving unit for driving the magnetic recording medium, a magnetic head for performing a recording operation on the magnetic recording medium, and a head driving unit for positioning the magnetic head with respect to the magnetic recording medium In a magnetic recording device having
The magnetic recording medium is formed by alternately laminating an underlayer made of Al or an alloy containing Al as a main component, and a layer containing Co as a main component and a layer containing Pd as a main component formed on the underlayer. A perpendicular magnetic recording type magnetic recording medium comprising a recording layer made of a laminated film,
The magnetic head has a means for heating the recording layer and a magnetic pole for applying a perpendicular magnetization to the heated recording layer region.
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JP2010182386A (en) * 2009-02-09 2010-08-19 Fuji Electric Device Technology Co Ltd Magnetic recording medium
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JP2010027159A (en) * 2008-07-22 2010-02-04 Fujitsu Ltd Method of manufacturing magnetic recording medium, magnetic recording medium, and information storage device
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