JP2001344726A - Perpendicular magnetic recording medium and magnetic storage device - Google Patents
Perpendicular magnetic recording medium and magnetic storage deviceInfo
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- JP2001344726A JP2001344726A JP2000158925A JP2000158925A JP2001344726A JP 2001344726 A JP2001344726 A JP 2001344726A JP 2000158925 A JP2000158925 A JP 2000158925A JP 2000158925 A JP2000158925 A JP 2000158925A JP 2001344726 A JP2001344726 A JP 2001344726A
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- magnetic
- film
- magnetic film
- recording medium
- alloy
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、再生ノイズが小さ
く、記録磁化の安定性に優れた超高密度磁気記録に好適
な垂直磁気記録媒体及び磁気記憶装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a perpendicular magnetic recording medium and a magnetic storage device which are suitable for ultra-high-density magnetic recording and have low reproduction noise and excellent recording magnetization stability.
【０００２】[0002]
【従来の技術】現在、実用的に用いられている磁気記録
方式は、磁気記録媒体面に平行に、かつ磁極のＮ極とＮ
極、Ｓ極とＳ極を互いに突き合わせる方向に磁化して磁
気記録を行う面内磁気記録方式である。面内磁気記録方
式において線記録密度を向上するには、記録時の反磁界
の影響を減少するために記録媒体である磁性膜の残留磁
化Ｂｒと磁性膜厚ｔの積Ｂｒ・ｔを小さくし、保磁力を
増大する必要がある。また、磁化遷移から発生する媒体
ノイズを減少するために、磁性膜の磁化容易軸を基板面
に平行に配向させると共に、結晶粒径の制御が必要であ
る。2. Description of the Related Art Currently, practically used magnetic recording systems include an N-pole and an N-pole, which are parallel to the surface of a magnetic recording medium and are magnetic poles.
This is an in-plane magnetic recording system in which magnetic recording is performed by magnetizing the poles, the S pole, and the S pole in a direction in which they face each other. In order to improve the linear recording density in the longitudinal magnetic recording method, the product Br · t of the residual magnetization Br and the magnetic film thickness t of the magnetic film as the recording medium is reduced to reduce the effect of the demagnetizing field during recording. , It is necessary to increase the coercive force. Further, in order to reduce the medium noise generated from the magnetization transition, it is necessary to orient the easy axis of the magnetic film parallel to the substrate surface and to control the crystal grain size.
【０００３】面内磁気記録用の磁性膜としては、Ｃｏを
主成分とし、これにＣｒ，Ｔａ，Ｐｔ，Ｒｈ，Ｐｄ，Ｔ
ｉ，Ｎｉ，Ｎｂ，Ｈｆなどを添加したＣｏ合金薄膜が用
いられる。磁性薄膜を構成するＣｏ合金は、主として六
方稠密格子構造（以下、ｈｃｐ構造という）の材料を用
いる。この結晶のｃ軸は＜００．１＞方向に磁化容易軸
を持ち、この磁化容易軸を面内方向に配向させる。磁性
薄膜の結晶配向性や粒径を制御するために、基板と磁性
膜の間に構造制御用の下地層を形成する。下地層として
は、Ｃｒを主成分とし、これにＴｉ，Ｍｏ，Ｖ，Ｗ，Ｐ
ｔ，Ｐｄなどを添加した材料を用いる。磁性薄膜は真空
蒸着法やスパッタリング法により形成する。またガラス
基板などを用いたとき面内磁化膜の結晶配向や磁気特性
改善のために前記Ｃｒ合金下地層の下層にＮｉ−Ａｌ合
金やＣｏ−Ｃｒ−Ｚｒ合金などのプリコートを形成した
媒体が用いられる。前記したように、面内磁気記録にお
いて媒体ノイズを小さくし線記録密度を向上するには、
磁性膜の残留磁化Ｂｒと磁性膜厚ｔの積を小さくする必
要があり、このために磁性膜の膜厚を２０ｎｍ以下まで
薄くし、結晶粒径を１０〜１５ｎｍまで微細化すること
が必要である。しかし、このような磁性結晶粒を微細化
した媒体では、熱揺らぎにより記録磁化が減少するとい
う極めて重大な問題があり、高密度記録の障害となって
いる。As a magnetic film for longitudinal magnetic recording, Co is used as a main component and Cr, Ta, Pt, Rh, Pd, T
A Co alloy thin film to which i, Ni, Nb, Hf or the like is added is used. As the Co alloy constituting the magnetic thin film, a material having a hexagonal close-packed lattice structure (hereinafter, referred to as an hcp structure) is mainly used. The c axis of the crystal has an easy axis in the <00.1> direction, and the easy axis is oriented in the in-plane direction. In order to control the crystal orientation and grain size of the magnetic thin film, an underlayer for structure control is formed between the substrate and the magnetic film. The base layer is mainly composed of Cr, and Ti, Mo, V, W, P
A material to which t, Pd, or the like is added is used. The magnetic thin film is formed by a vacuum evaporation method or a sputtering method. When a glass substrate or the like is used, a medium in which a precoat of a Ni-Al alloy or a Co-Cr-Zr alloy is formed under the Cr alloy underlayer to improve the crystal orientation and magnetic properties of the in-plane magnetized film is used. Can be As described above, in order to reduce medium noise and improve linear recording density in longitudinal magnetic recording,
It is necessary to reduce the product of the residual magnetization Br of the magnetic film and the magnetic film thickness t. For this purpose, it is necessary to reduce the film thickness of the magnetic film to 20 nm or less and to reduce the crystal grain size to 10 to 15 nm. is there. However, such a medium in which the magnetic crystal grains are made fine has a very serious problem that the recording magnetization decreases due to thermal fluctuation, which is an obstacle to high-density recording.
【０００４】一方、垂直磁気記録方式は、記録媒体面に
垂直に、かつ隣り合う記録ビットが互いに反平行になる
ように磁区を形成する磁気記録方式であり、記録ビット
の境界での反磁界が小さくなり高密度記録ほど磁化が安
定に保たれ易い利点があり、高密度磁気記録の有力な手
段の一つである。面内磁気記録による高密度記録のため
には、前記したように磁性膜の厚さを２０ｎｍ以下に
し、磁性結晶粒径の微細化と均一化をする必要がある
が、この場合、熱的緩和により記録磁化が消失する問題
がある。これに対して垂直磁気記録では、面内磁気記録
に比べて磁性膜厚を厚くでき、記録磁化を安定に保持で
きる利点がある。垂直磁気記録により線記録密度を向上
するためには、記録ビット内部及び磁化遷移領域に形成
される不規則構造の磁区から発生する媒体ノイズを減少
することが必要である。このためには、磁性膜の磁化容
易軸を基板面に垂直に配向させると共に、磁化容易軸の
配向分散を小さくし、結晶粒径を制御することが必要で
ある。On the other hand, the perpendicular magnetic recording system is a magnetic recording system in which magnetic domains are formed perpendicularly to the recording medium surface so that adjacent recording bits are antiparallel to each other. There is an advantage that the smaller the recording density is, the more easily the magnetization can be stably maintained as the recording density is high. This is one of the effective means of the high-density magnetic recording. For high-density recording by in-plane magnetic recording, as described above, it is necessary to reduce the thickness of the magnetic film to 20 nm or less and to make the magnetic crystal grain size finer and more uniform. Therefore, there is a problem that the recorded magnetization disappears. On the other hand, perpendicular magnetic recording has the advantage that the magnetic film thickness can be made larger than in-plane magnetic recording, and that the recorded magnetization can be stably maintained. In order to improve linear recording density by perpendicular magnetic recording, it is necessary to reduce medium noise generated from magnetic domains having irregular structures formed inside recording bits and in a magnetization transition region. To this end, it is necessary to align the easy axis of the magnetic film perpendicular to the substrate surface, reduce the orientation dispersion of the easy axis, and control the crystal grain size.
【０００５】垂直磁化膜としては、Ｃｏを主成分とし、
これにＣｒ，Ｔａ，Ｐｔ，Ｒｈ，Ｐｄ，Ｔｉ，Ｎｉ，Ｎ
ｂ，Ｈｆなどを添加したＣｏ合金薄膜、またはＣｏに希
土類元素を添加した例えばＴｅ−Ｆｅ−Ｃｏ非晶質材
料、ＣｏとＰｔやＰｄの多層膜材料などが用いられる。
磁性薄膜を構成するＣｏ合金としては、主としてｈｃｐ
構造の材料を用いる。Ｃｏ合金薄膜は、この結晶のｃ
軸、＜００．１＞方向に磁化容易軸を持ち、この磁化容
易軸を記録媒体面に垂直方向に配向させる。磁性薄膜は
真空蒸着法やスパッタリング法により形成する。磁気記
録したときの線記録密度や再生出力を向上し、再生ノイ
ズを減少させて磁気記録特性を向上するために、上記の
Ｃｏ合金薄膜のｃ軸の垂直配向性を向上すると共に、結
晶粒径の制御が必要であり、このために基板と磁性膜の
間に構造制御用の下地層を形成するなどの改善策が従来
から行われている。The perpendicular magnetization film has Co as a main component,
This includes Cr, Ta, Pt, Rh, Pd, Ti, Ni, N
For example, a Co alloy thin film to which b, Hf, or the like is added, a Te—Fe—Co amorphous material in which a rare earth element is added to Co, or a multilayer film material of Co and Pt or Pd is used.
As the Co alloy constituting the magnetic thin film, mainly hcp
Use structural materials. The Co alloy thin film has the c
The axis has an easy axis in the <00.1> direction, and the easy axis is oriented in a direction perpendicular to the recording medium surface. The magnetic thin film is formed by a vacuum evaporation method or a sputtering method. In order to improve the linear recording density and reproducing output when magnetic recording is performed, to reduce reproducing noise and to improve magnetic recording characteristics, the Co alloy thin film is improved in c-axis vertical orientation and crystal grain size. Therefore, improvement measures such as forming an underlayer for structure control between the substrate and the magnetic film have been conventionally taken.
【０００６】垂直磁気記録媒体には、基板上に構造制御
層を介して垂直磁化膜を形成した単層垂直磁気記録媒体
と、基板上に軟磁性膜を形成し、この上に構造制御層を
介して垂直磁化膜を形成した２層垂直磁気記録媒体があ
る。前者の場合、媒体ノイズの主因は、反磁界の影響に
より記録ビット内部及び磁化遷移領域に形成される不規
則構造の磁区である。一方、後者の２層垂直磁気記録媒
体の場合、媒体ノイズは、記録ビット内部及び磁化遷移
領域に形成される不規則構造の磁区に加えて、垂直磁化
膜の下層に設けた軟磁性膜など裏打磁性層の磁区構造の
乱れによっても発生する。[0006] The perpendicular magnetic recording medium includes a single-layer perpendicular magnetic recording medium having a perpendicular magnetization film formed on a substrate via a structure control layer, and a soft magnetic film formed on a substrate, and a structure control layer formed thereon. There is a two-layer perpendicular magnetic recording medium in which a perpendicular magnetization film is formed through the medium. In the former case, the main cause of the medium noise is a magnetic domain having an irregular structure formed inside the recording bit and in the magnetization transition region due to the influence of the demagnetizing field. On the other hand, in the case of the latter two-layer perpendicular magnetic recording medium, the medium noise is caused by irregular magnetic domains formed in the recording bit and in the magnetization transition region, as well as the soft magnetic film provided under the perpendicular magnetization film. It is also caused by disturbance of the magnetic domain structure of the magnetic layer.
【０００７】軟磁性膜の磁区構造を制御する方式とし
て、例えば特開平１１−１９１２１７号公報「垂直磁気
記録媒体の製造方法」のように、軟磁性膜の下層に磁化
容易磁区が面内方向に配向した硬磁性膜を形成する方法
が提案されている。この方法によれば、外部磁界による
軟磁性膜の磁区構造の変化をある程度低下できる効果は
認められるが、軟磁性膜の下層に直接面内配向の硬磁性
膜を接して形成することにより硬磁性膜の磁区構造がこ
の上の軟磁性膜に転写され、その結果、軟磁性膜から発
生したノイズが垂直磁化膜の再生信号の中に含まれて高
密度記録の障害になる問題がある。As a method for controlling the magnetic domain structure of the soft magnetic film, for example, as described in Japanese Patent Application Laid-Open No. H11-191217, "Method for Manufacturing a Perpendicular Magnetic Recording Medium", easy magnetic domains are formed in the in-plane direction below the soft magnetic film. A method for forming an oriented hard magnetic film has been proposed. According to this method, the effect of reducing the change of the magnetic domain structure of the soft magnetic film due to an external magnetic field is recognized to some extent, but the hard magnetic film is formed by directly contacting the in-plane oriented hard magnetic film below the soft magnetic film. The magnetic domain structure of the film is transferred to the soft magnetic film thereon, and as a result, there is a problem that noise generated from the soft magnetic film is included in the reproduction signal of the perpendicular magnetization film and causes an obstacle to high density recording.
【０００８】[0008]
【発明が解決しようとする課題】垂直磁気記録媒体、特
に２層垂直磁気記録媒体により超高密度磁気記録を実現
するには、線記録密度の向上の他に再生信号に含まれる
ノイズ、特に媒体の微細構造に起因する媒体ノイズを低
減し、かつ記録磁化を安定に保つことが重要である。本
発明は、このような問題認識のもとに、従来技術の欠点
を解消し、優れた低ノイズ特性と記録磁化の安定性を有
し超高密度磁気記録に好適な垂直磁気記録媒体及び磁気
記憶装置を提供することを目的とする。In order to realize ultra-high-density magnetic recording with a perpendicular magnetic recording medium, especially a two-layer perpendicular magnetic recording medium, it is necessary to improve the linear recording density and to improve the noise included in the reproduced signal, especially the medium. It is important to reduce the medium noise caused by the fine structure and to keep the recording magnetization stable. The present invention, based on recognition of such a problem, solves the drawbacks of the prior art, and has excellent low noise characteristics and stable recording magnetization, and has a perpendicular magnetic recording medium and a magnetic recording medium suitable for ultra-high density magnetic recording. It is an object to provide a storage device.
【０００９】[0009]
【課題を解決するための手段】本発明者らは、裏打磁性
層を備えた垂直磁気記録媒体における記録磁化の安定性
を妨げる要因及び媒体ノイズの原因について詳細に検討
した結果、裏打磁性層表面の磁区構造が磁気記録したと
きの垂直磁気記録媒体表面の漏洩磁界分布に影響し、媒
体ノイズを増大させ、記録磁化の安定性を阻害している
ことを見出した。Means for Solving the Problems The present inventors have examined in detail the factors which hinder the stability of the recording magnetization and the causes of the medium noise in a perpendicular magnetic recording medium having a backing magnetic layer, and as a result, It was found that the magnetic domain structure affected the leakage magnetic field distribution on the surface of the perpendicular magnetic recording medium during magnetic recording, increased the medium noise, and hindered the stability of recording magnetization.
【００１０】裏打磁性層を備えた垂直磁気記録媒体にお
いて、裏打磁性層は、（１）垂直磁気記録の際の記録ヘ
ッドの記録効率向上のためのリターンパスの役割と、
（２）垂直磁化膜からの再生信号出力向上の役割とを主
たる目的として従来用いられている。本発明では、裏打
磁性層の構造と表面の磁区構造の関係、および裏打磁性
層と垂直磁化膜の相互作用による磁区構造の関係、特に
裏打磁性層に含まれる硬磁性膜の結晶配向と磁区構造の
関係を系統的に調べ、垂直磁気記録媒体の媒体ノイズ低
減に好適な手段を見い出した。In a perpendicular magnetic recording medium having a backing magnetic layer, the backing magnetic layer serves as (1) a role of a return path for improving the recording efficiency of a recording head during perpendicular magnetic recording;
(2) It is conventionally used mainly for the purpose of improving the reproduction signal output from the perpendicular magnetization film. In the present invention, the relationship between the structure of the backing magnetic layer and the magnetic domain structure on the surface, and the relationship between the magnetic domain structure due to the interaction between the backing magnetic layer and the perpendicular magnetization film, particularly the crystal orientation and the magnetic domain structure of the hard magnetic film contained in the backing magnetic layer Was systematically examined, and a suitable means for reducing the medium noise of the perpendicular magnetic recording medium was found.
【００１１】本発明においては、垂直磁化膜の結晶配向
及び結晶粒径制御に加えて垂直磁化膜の下層に形成する
裏打磁性層の構造を制御することによって、特に裏打磁
性層表面の磁区構造を制御し、磁気記録したとき垂直磁
化膜表面に形成される不規則構造の磁区を低減すること
により、前記目的を達成する。具体的には、基板上に裏
打磁性層、垂直磁化膜、保護膜の順に形成した垂直磁気
記録媒体において、裏打磁性層を組成もしくは保磁力の
異なる磁性膜を積層した構造とし、裏打磁性層の構造と
表面の磁区構造の関係を系統的に調べることにより、媒
体ノイズの小さい記録磁化の安定性に優れた超高密度磁
気記録に好適な垂直磁気記録媒体を提供する。In the present invention, by controlling the structure of the backing magnetic layer formed below the perpendicular magnetization film in addition to controlling the crystal orientation and crystal grain size of the perpendicular magnetization film, the magnetic domain structure on the surface of the backing magnetic layer can be particularly improved. The object is achieved by controlling and reducing the magnetic domains of the irregular structure formed on the surface of the perpendicular magnetization film when performing magnetic recording. Specifically, in a perpendicular magnetic recording medium in which a backing magnetic layer, a perpendicular magnetic film, and a protective film are formed in this order on a substrate, the backing magnetic layer has a structure in which magnetic films having different compositions or coercive forces are laminated, and By systematically examining the relationship between the structure and the magnetic domain structure on the surface, it is possible to provide a perpendicular magnetic recording medium suitable for ultra-high-density magnetic recording with small medium noise and excellent recording magnetization stability.
【００１２】すなわち、本発明による垂直磁気記録媒体
は、基板上に裏打磁性層を介して垂直磁化膜を設けた垂
直磁気記録媒体において、裏打磁性層は基板に近い側に
形成した磁化容易軸が垂直配向した硬磁性膜と、硬磁性
膜の上に形成した軟磁性膜とを含むことを特徴とする。That is, in the perpendicular magnetic recording medium according to the present invention, in a perpendicular magnetic recording medium in which a perpendicular magnetic film is provided on a substrate via a backing magnetic layer, the backing magnetic layer has an easy axis of magnetization formed on the side close to the substrate. It is characterized by including a vertically oriented hard magnetic film and a soft magnetic film formed on the hard magnetic film.
【００１３】硬磁性膜は保磁力が１ｋＯｅ以上であり、
軟磁性膜は保磁力が１Ｏｅ以下の非晶質軟磁性膜とする
ことができる。また、硬磁性膜は保磁力が１ｋＯｅ以上
であり、軟磁性膜は多結晶性軟磁性膜上に非晶質軟磁性
膜が形成された積層構造を有し保磁力が１Ｏｅ以下であ
る膜とすることができる。The hard magnetic film has a coercive force of 1 kOe or more,
The soft magnetic film can be an amorphous soft magnetic film having a coercive force of 1 Oe or less. The hard magnetic film has a coercive force of 1 kOe or more, and the soft magnetic film has a laminated structure in which an amorphous soft magnetic film is formed on a polycrystalline soft magnetic film and has a coercive force of 1 Oe or less. can do.
【００１４】非晶質軟磁性膜はＣｏ−Ｎｂ−Ｚｒ系非晶
質合金、Ｃｏ−Ｍｏ−Ｚｒ系非晶質合金、Ｃｏ−Ｗ−Ｚ
ｒ系非晶質合金、Ｃｏ−Ｔａ−Ｚｒ系非晶質合金、Ｃｏ
−Ｎｉ−Ｚｒ系非晶質合金から選ばれる何れかの材料で
構成することができ、多結晶性軟磁性膜はＦｅ−Ａｌ−
Ｓｉ−Ｍ合金（Ｍ：Ｃｒ，Ｔｉ）、Ｆｅ−Ｔａ−Ｃ−Ｍ
合金（Ｍ：Ａｌ，Ｃｒ）、Ｆｅ−Ｈｆ−Ｃ−Ｍ合金
（Ｍ：Ａｌ，Ｃｒ）、Ｆｅ−Ｔａ−Ｎ−Ｍ合金（Ｍ：Ａ
ｌ，Ｃｒ）、Ｎｉ−Ｆｅ−Ｍ合金（Ｍ：Ｎｂ，Ｍｏ）か
ら選ばれる何れかの材料で構成することができ、硬磁性
膜はＣｏを主成分としこれにＣｒ，Ｐｔ，Ｔａ，Ｈｆ，
Ｓｍの何れかを添加した合金で構成することができる。
ここで、表記（Ｍ：ａ，ｂ）は、Ｍがａ又はｂであるこ
とを表す。裏打磁性層と垂直磁化膜の間に膜厚１〜１０
ｎｍの非磁性の構造制御層を含むことが好ましい。The amorphous soft magnetic film is made of a Co-Nb-Zr-based amorphous alloy, a Co-Mo-Zr-based amorphous alloy, or a Co-WZ
r-based amorphous alloy, Co-Ta-Zr-based amorphous alloy, Co
-Ni-Zr-based amorphous alloy, the polycrystalline soft magnetic film may be made of Fe-Al-
Si-M alloy (M: Cr, Ti), Fe-Ta-CM
Alloy (M: Al, Cr), Fe-Hf-CM alloy (M: Al, Cr), Fe-Ta-NM alloy (M: A
1, Cr) and Ni-Fe-M alloy (M: Nb, Mo), and the hard magnetic film contains Co as a main component and contains Cr, Pt, Ta, and Hf. ,
It can be composed of an alloy to which any of Sm is added.
Here, the notation (M: a, b) indicates that M is a or b. A film thickness of 1 to 10 between the backing magnetic layer and the perpendicular magnetization film
It is preferable to include a nonmagnetic structure control layer having a thickness of nm.
【００１５】本発明による磁気記憶装置は、磁気記録媒
体と、磁気記録媒体を駆動する駆動手段と、記録部と再
生部とを備える磁気ヘッドと、磁気ヘッドを磁気記録媒
体に対して相対的に移動させる磁気ヘッド駆動手段と、
磁気ヘッドの記録信号及び再生信号を処理する信号処理
手段とを備える磁気記憶装置において、磁気記録媒体と
して前述の垂直磁気記録媒体を用いたことを特徴とす
る。磁気ヘッドの記録部は、リング型もしくは単磁極型
の磁気記録用ヘッドで構成することができる。また、磁
気ヘッドの再生部は、磁気抵抗効果型、スピンバルブ型
もしくは磁気トンネル型の信号再生用ヘッドで構成する
ことができる。A magnetic storage device according to the present invention has a magnetic recording medium, a driving unit for driving the magnetic recording medium, a magnetic head including a recording unit and a reproducing unit, and a magnetic head relatively to the magnetic recording medium. Magnetic head driving means for moving,
A magnetic storage device comprising a signal processing means for processing a recording signal and a reproduction signal of a magnetic head, wherein the above-described perpendicular magnetic recording medium is used as a magnetic recording medium. The recording section of the magnetic head can be constituted by a ring-type or single-pole type magnetic recording head. The reproducing section of the magnetic head can be constituted by a magneto-resistive, spin-valve or magnetic tunnel type signal reproducing head.
【００１６】[0016]
【発明の実施の形態】以下に本発明の実施例を挙げ、図
面を参照しながら詳細に説明する。図において、同一の
符号を付した部分は、同じ性能特性を有する部分を示
す。DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. In the figure, the portions denoted by the same reference numerals indicate portions having the same performance characteristics.
【００１７】〔実施例１〕本発明による垂直磁気記録媒
体は、基板面の片面もしくは両面に記録層を設けること
が可能であり、図１は、本発明による垂直磁気記録媒体
の基本構造の一例を示す断面模式図である。図１に示す
垂直磁気記録媒体は、基板１１上に裏打磁性層１２、垂
直磁化膜の構造制御層１５、垂直磁化膜１６、及び保護
膜１７を有する。裏打磁性層１２は、高保磁力の硬磁性
膜１３と軟磁性膜１４とで構成される積層構造である。
高保磁力の硬磁性膜１３は、この上に形成する軟磁性膜
１４の磁区構造が外部磁界によって変化するのを防止す
る役割があり、その保磁力は上部に形成する軟磁性膜１
４より大きく２０〜４０００Ｏｅの範囲、望ましくは１
０００〜４０００Ｏｅの範囲が良い。高保磁力の硬磁性
膜１３は、磁化容易軸が基板面に垂直方向に配向した材
料を用いる。また軟磁性膜１４の保磁力は、２０Ｏｅ以
下が良く、望ましくは１Ｏｅ以下が望ましい。更に軟磁
性膜１４は保磁力の異なる材料を積層して用いることも
可能である。[Embodiment 1] A perpendicular magnetic recording medium according to the present invention can be provided with a recording layer on one or both sides of a substrate surface. FIG. 1 shows an example of a basic structure of a perpendicular magnetic recording medium according to the present invention. FIG. The perpendicular magnetic recording medium shown in FIG. 1 has a backing magnetic layer 12, a perpendicular magnetic film structure control layer 15, a perpendicular magnetic film 16, and a protective film 17 on a substrate 11. The backing magnetic layer 12 has a laminated structure composed of a hard magnetic film 13 having a high coercive force and a soft magnetic film 14.
The hard magnetic film 13 having a high coercive force has a role of preventing the magnetic domain structure of the soft magnetic film 14 formed thereon from being changed by an external magnetic field.
Greater than 4 and in the range of 20-4000 Oe, preferably 1
The range of 000 to 4000 Oe is good. For the hard magnetic film 13 having a high coercive force, a material whose easy axis of magnetization is oriented in a direction perpendicular to the substrate surface is used. The coercive force of the soft magnetic film 14 is preferably 20 Oe or less, and more preferably 1 Oe or less. Further, the soft magnetic film 14 may be formed by laminating materials having different coercive forces.
【００１８】高真空ＤＣマグネトロンスパッタリング装
置により、図１に断面構造を示す媒体を作製した。洗浄
したガラス基板１１をスパッタリング装置に設置し、続
いて基板１１を約３００℃に加熱した。高保磁力の硬磁
性膜１３として磁化容易軸が基板面に垂直方向に配向し
た試料を作製した。まず上記基板上にプリコート層を形
成した。プリコート層は、この上に形成する垂直配向の
硬磁性膜１３の結晶配向を促進するために用いるもの
で、Ｔｉ，Ｈｆ，Ｔｉ−Ｃｒ合金、Ｈｆ−Ｃｒ合金、非
磁性のＣｏ−Ｃｒ合金あるいはＳｉ，Ｇｅ，Ｃなどの非
晶質材料を用いることができる。本実施例では膜厚３０
ｎｍのＴｉ−１０ａｔ％Ｃｒ合金を用いた。Using a high vacuum DC magnetron sputtering apparatus, a medium having a sectional structure shown in FIG. 1 was produced. The washed glass substrate 11 was set in a sputtering apparatus, and subsequently, the substrate 11 was heated to about 300 ° C. As the hard magnetic film 13 having a high coercive force, a sample having an easy axis of magnetization oriented in a direction perpendicular to the substrate surface was prepared. First, a precoat layer was formed on the substrate. The precoat layer is used to promote the crystal orientation of the vertically oriented hard magnetic film 13 formed thereon, and includes Ti, Hf, Ti—Cr alloy, Hf—Cr alloy, non-magnetic Co—Cr alloy, An amorphous material such as Si, Ge, and C can be used. In this embodiment, the film thickness is 30.
nm Ti-10 at% Cr alloy was used.
【００１９】このプリコート層の上に膜厚２０ｎｍの非
磁性Ｃｏ−３５ａｔ％Ｃｒ合金膜を介して膜厚２５ｎｍ
の磁化容易軸が垂直配向した硬磁性膜１３を形成した。
硬磁性膜１３としては、Ｃｏを主成分とし、これにＣ
ｒ，Ｔａ，Ｐｔ，Ｒｈ，Ｐｄ，Ｔｉ，Ｎｉ，Ｎｂ，Ｈｆ
などを添加したＣｏ合金薄膜、またはＣｏに希土類元素
を添加した材料を用いることができるが、本実施例では
Ｃｏ−１８ａｔ％Ｃｒ−１４ａｔ％Ｐｔ−３ａｔ％Ｔａ
合金を用いた例で説明する。硬磁性膜１３の膜面垂直方
向の保磁力は３０００Ｏｅ、角型比（ＳＱ＝残留磁化と
飽和磁化の比）は０．８２であった。続いて、この硬磁
性膜１３の上に軟磁性膜１４としてＣｏ−１０ａｔ％Ｔ
ａ−５ａｔ％Ｚｒ非晶質合金膜を形成した。軟磁性膜１
４の保磁力は０．３Ｏｅ、初透磁率は５００であった。
軟磁性膜１４の磁区構造に及ぼす硬磁性膜１３の影響を
調べるために、軟磁性膜の膜厚を０〜４００ｎｍの範囲
で変化させた試料を作製した。On this pre-coat layer, a non-magnetic Co-35 at% Cr alloy film having a film thickness of 20 nm is interposed to form a film having a film thickness of 25 nm.
The hard magnetic film 13 whose easy axis of magnetization was vertically oriented was formed.
The hard magnetic film 13 contains Co as a main component,
r, Ta, Pt, Rh, Pd, Ti, Ni, Nb, Hf
A Co alloy thin film to which Co or the like is added or a material to which Co is added a rare earth element can be used. In this embodiment, Co-18 at% Cr-14 at% Pt-3 at% Ta is used.
An example using an alloy will be described. The coercive force in the direction perpendicular to the film surface of the hard magnetic film 13 was 3000 Oe, and the squareness ratio (SQ = the ratio of residual magnetization to saturation magnetization) was 0.82. Subsequently, a Co-10 at% T is formed on the hard magnetic film 13 as a soft magnetic film 14.
An a-5 at% Zr amorphous alloy film was formed. Soft magnetic film 1
The coercive force of No. 4 was 0.3 Oe, and the initial magnetic permeability was 500.
In order to examine the effect of the hard magnetic film 13 on the magnetic domain structure of the soft magnetic film 14, a sample was manufactured in which the thickness of the soft magnetic film was changed in the range of 0 to 400 nm.
【００２０】軟磁性膜１４の上に構造制御層１５を形成
し、その上に膜厚２０ｎｍの垂直磁化膜１６、膜厚５ｎ
ｍの保護膜１７を順次形成した。構造制御層１５は、こ
の上に形成する垂直磁化膜１６の結晶配向を向上する役
割と結晶粒径を制御する役割があり、Ｔｉ，Ｈｆ，Ｔｉ
−Ｃｒ合金、Ｈｆ−Ｃｒ合金、あるいは非磁性のＣｏ−
Ｃｒ合金などのｈｃｐ構造の材料、Ｓｉ，Ｇｅ，Ｃなど
の非晶質材料を用いることができる。ここでは、構造制
御層１５として、膜厚５ｎｍのＴｉ−１０ａｔ％Ｃｒ合
金を用いた例で説明する。垂直磁化膜１６としてはＣｏ
−１８ａｔ％Ｃｒ−１２ａｔ％Ｐｔ−３ａｔ％Ｔａ合金
を用い、保護膜１７としてはカーボンを用いた。垂直磁
化膜１６の膜面垂直方向の保磁力は３１００Ｏｅ、角型
比は０．９であった。A structure control layer 15 is formed on the soft magnetic film 14, and a 20 nm-thick perpendicular magnetization film 16 and a 5n-thick
m protective films 17 were sequentially formed. The structure control layer 15 has a role of improving the crystal orientation of the perpendicular magnetization film 16 formed thereon and a role of controlling the crystal grain size.
-Cr alloy, Hf-Cr alloy, or non-magnetic Co-
An hcp structure material such as a Cr alloy or an amorphous material such as Si, Ge, or C can be used. Here, an example in which a Ti-10 at% Cr alloy having a thickness of 5 nm is used as the structure control layer 15 will be described. As the perpendicular magnetization film 16, Co is used.
An alloy of -18 at% Cr-12 at% Pt-3 at% Ta was used, and carbon was used as the protective film 17. The coercive force of the perpendicular magnetization film 16 in the direction perpendicular to the film surface was 3100 Oe, and the squareness ratio was 0.9.
【００２１】比較のために、硬磁性膜１３として磁化容
易軸が基板面に平行に配向した試料を作製した。まず上
記基板上にプリコート層として膜厚５０ｎｍのＮｉ−５
０ａｔ％Ａｌ合金膜を形成し、この上に高保磁力の硬磁
性膜１３の結晶配向制御用の下地層として膜厚２０ｎｍ
のＣｒ膜を形成した。このＣｒ膜は＜１１０＞もしくは
＜１００＞方位に配向していた。硬磁性膜１３の結晶配
向を向上するために、上記のＣｒ膜の上にＣｒＴｉ
ｘ（ｘ＝１０〜２０ａｔ％）やＣｒＭｏｘ（ｘ＝１０〜
２０ａｔ％）、あるいはＣｒＶｘ（ｘ＝１０〜２０ａｔ
％）膜を形成して用いることも可能である。For comparison, a sample was prepared as the hard magnetic film 13 in which the axis of easy magnetization was oriented parallel to the substrate surface. First, a Ni-5 layer having a thickness of 50 nm was formed on the substrate as a precoat layer.
A 0 at% Al alloy film is formed, and a 20 nm-thick film is formed thereon as an underlayer for controlling the crystal orientation of the hard magnetic film 13 having a high coercive force.
Was formed. This Cr film was oriented in the <110> or <100> direction. In order to improve the crystal orientation of the hard magnetic film 13, a CrTi film is formed on the Cr film.
x (x = 10 to 20 at%) and CrMo x (x = 10 to 20 at%)
20 at%) or CrV x (x = 10 to 20 at)
%) It is also possible to form and use a film.
【００２２】この下地層の上に高保磁力の硬磁性膜１３
として膜厚２５ｎｍのＣｏ−１８ａｔ％Ｃｒ−１４ａｔ
％Ｐｔ−３ａｔ％Ｔａ薄膜を形成した。この硬磁性膜１
３は、ｈｃｐ構造のｃ軸が基板面にほぼ平行に配向して
いた。硬磁性膜１３の面内方向の保磁力は２５００Ｏ
ｅ、角型比（ＳＱ＝残留磁化と飽和磁化の比）は０．８
２であった。続いて、この硬磁性膜１３の上に軟磁性膜
１４としてＣｏ−１０ａｔ％Ｔａ−５ａｔ％Ｚｒ非晶質
合金膜を形成した。軟磁性膜１４の磁区構造に及ぼす硬
磁性膜１３の影響を調べるために、軟磁性膜の膜厚を０
〜４００ｎｍの範囲で変化させた試料を作製した。軟磁
性膜１４の上に構造制御層１５を形成し、その上に膜厚
２０ｎｍの垂直磁化膜１６、膜厚５ｎｍの保護膜１７を
順次形成した。垂直磁化膜１６としてはＣｏ−１８ａｔ
％Ｃｒ−１２ａｔ％Ｐｔ−３ａｔ％Ｔａ合金を用い、保
護膜１７としてはカーボンを用いた。垂直磁化膜１６の
膜面垂直方向の保磁力は３０８０Ｏｅ、角型比は０．８
９であった。On this underlayer, a hard magnetic film 13 having a high coercive force is formed.
Co-18 at% Cr-14 at 25 nm in thickness
% Pt-3 at% Ta thin film was formed. This hard magnetic film 1
In No. 3, the c-axis of the hcp structure was oriented almost parallel to the substrate surface. The coercive force in the in-plane direction of the hard magnetic film 13 is 2500O.
e, squareness ratio (SQ = ratio of residual magnetization to saturation magnetization) is 0.8
It was 2. Subsequently, a Co-10 at% Ta-5 at% Zr amorphous alloy film was formed as a soft magnetic film 14 on the hard magnetic film 13. In order to investigate the effect of the hard magnetic film 13 on the magnetic domain structure of the soft magnetic film 14, the thickness of the soft magnetic film was set to 0.
Samples varied in the range of ４００400 nm were prepared. A structure control layer 15 was formed on the soft magnetic film 14, and a 20 nm-thick perpendicular magnetic film 16 and a 5 nm-thick protective film 17 were sequentially formed thereon. Co-18at is used as the perpendicular magnetization film 16.
% Cr-12 at% Pt-3 at% Ta alloy was used, and carbon was used as the protective film 17. The coercive force of the perpendicular magnetization film 16 in the direction perpendicular to the film surface is 3080 Oe, and the squareness ratio is 0.8.
Nine.
【００２３】図２は、磁区構造比較用テスト試料の構成
を示す。図中の（イ）〜（ニ）はその高さ位置まで成膜
したことを示しており、（イ）は硬磁性膜１３までを形
成した試料、（ロ）は硬磁性膜１３の上に膜厚４０ｎｍ
のＣｏ−Ｔａ−Ｚｒ軟磁性膜１４を形成した試料、
（ハ）は硬磁性膜１３の上に膜厚４００ｎｍのＣｏ−Ｔ
ａ−Ｚｒ軟磁性膜１４を形成した試料、（ニ）は前記軟
磁性膜１４の上に構造制御層１５と膜厚２０ｎｍのＣｏ
−１８ａｔ％Ｃｒ−１２ａｔ％Ｐｔ−３ａｔ％Ｔａ合金
垂直磁化膜１６、膜厚５ｎｍのカーボン保護膜１７を順
次形成した試料である。硬磁性膜１３としては、磁化容
易軸が膜面に垂直方向に配向した本発明の媒体と磁化容
易軸が膜面に平行に配向した比較用の試料を作製した。FIG. 2 shows the structure of a magnetic domain structure comparison test sample. (A) to (D) in the figure indicate that the film was formed up to the height position, (A) is a sample formed up to the hard magnetic film 13, (B) is on the hard magnetic film 13 Thickness 40nm
Sample on which the Co-Ta-Zr soft magnetic film 14 was formed,
(C) shows a 400 nm thick Co-T film on the hard magnetic film 13.
The sample on which the a-Zr soft magnetic film 14 was formed, (d) shows a structure control layer 15 and a 20 nm thick Co on the soft magnetic film 14.
This is a sample in which a -18 at% Cr-12 at% Pt-3 at% Ta alloy perpendicular magnetization film 16 and a 5 nm-thick carbon protective film 17 are sequentially formed. As the hard magnetic film 13, a medium of the present invention in which the easy axis was oriented in the direction perpendicular to the film surface and a comparative sample in which the easy axis was oriented parallel to the film surface were prepared.
【００２４】図３に、上記テスト試料の残留磁化状態に
おける磁区構造を比較して示す。磁区構造は磁気力顕微
鏡で計測した。図において、（ａ）の列は本発明による
媒体の磁区構造を示し、（ｂ）の列は比較用媒体の磁区
構造を示している。（ａ）の列及び（ｂ）の列の（イ）
〜（ニ）は、図２に示した媒体構成に対応する。例え
ば、（イ）は硬磁性膜１３の表面（軟磁性膜厚０ｎｍ）
の磁区構造を示し、同様に、（ロ）は硬磁性膜１３の上
に形成された膜厚４０ｎｍの軟磁性膜表面の磁区構造
を、（ハ）は硬磁性膜１３の上に形成された膜厚４００
ｎｍの軟磁性膜表面の磁区構造を、（ニ）は保護膜１７
の表面の磁区構造をそれぞれ示している。FIG. 3 shows a comparison of the magnetic domain structure in the remanent magnetization state of the test sample. The domain structure was measured with a magnetic force microscope. In the figure, the column (a) shows the magnetic domain structure of the medium according to the present invention, and the column (b) shows the magnetic domain structure of the comparative medium. (A) of the row of (a) and the row of (b)
(D) correspond to the medium configuration shown in FIG. For example, (a) shows the surface of the hard magnetic film 13 (soft magnetic film thickness 0 nm)
Similarly, (b) shows the magnetic domain structure on the surface of the soft magnetic film having a thickness of 40 nm formed on the hard magnetic film 13, and (c) shows the magnetic domain structure formed on the hard magnetic film 13. Thickness 400
the magnetic domain structure on the surface of the soft magnetic film of
Shows the magnetic domain structure on the surface of each.
【００２５】この磁区構造において、明暗のコントラス
トで磁区構造の乱れが示されている。図において黒いコ
ントラストで観察される領域が、媒体ノイズの原因とな
る不規則構造の磁区であり、不規則構造磁区の寸法が小
さいほど、また磁区から発生する信号が小さいほどノイ
ズが小さい。本発明のように垂直配向した硬磁性膜１３
の上に軟磁性膜１４を形成した媒体では、図３（ａ）の
（イ）〜（ハ）に示すように、軟磁性膜表面の不規則構
造磁区の寸法が小さい。一方、面内配向した硬磁性膜の
上に軟磁性膜を形成した比較用媒体（ｂ）では、軟磁性
膜表面の不規則構造磁区の寸法が大きく、磁気ヘッドで
再生したとき特に長波長成分のノイズ信号の源となる。
また、図３から分かるように、比較用媒体では、軟磁性
膜厚と共に表面の磁区構造が大きく変化する。すなわち
軟磁性膜厚が薄いときは下層の硬磁性膜表面の磁区構造
の乱れが強調されて現れ、軟磁性膜厚が厚くなると大き
なサイズの磁区が表面に形成され易い傾向が認められ
る。一方、本発明の媒体では磁区構造の軟磁性膜厚依存
性が小さく、また磁区サイズも小さく媒体ノイズ低減効
果が大きい。In this magnetic domain structure, disturbance of the magnetic domain structure is shown by light and dark contrast. In the figure, a region observed with black contrast is a magnetic domain having an irregular structure that causes medium noise. The smaller the size of the irregular magnetic domain and the smaller the signal generated from the magnetic domain, the smaller the noise. Hard magnetic film 13 vertically oriented as in the present invention
In the medium on which the soft magnetic film 14 is formed, the size of the irregular magnetic domain on the surface of the soft magnetic film is small as shown in FIGS. On the other hand, in the comparative medium (b) in which the soft magnetic film was formed on the in-plane oriented hard magnetic film, the size of the irregular magnetic domains on the surface of the soft magnetic film was large, and especially when reproduced by a magnetic head, the long wavelength component Is a source of the noise signal.
Further, as can be seen from FIG. 3, in the comparative medium, the magnetic domain structure on the surface changes greatly with the soft magnetic film thickness. That is, when the soft magnetic film thickness is small, disturbance of the magnetic domain structure on the surface of the lower hard magnetic film is emphasized and appears. When the soft magnetic film thickness is large, a large magnetic domain tends to be easily formed on the surface. On the other hand, in the medium of the present invention, the dependence of the magnetic domain structure on the soft magnetic film thickness is small, the magnetic domain size is small, and the effect of reducing the medium noise is large.
【００２６】前記軟磁性膜の上に垂直磁化膜を形成した
試料、すなわち図３（ニ）に対応する試料のノイズスペ
クトラムを測定し、不規則磁区からの信号を定量的に比
較した。その結果を図４に示す。図４において、横軸は
ノイズ信号の波長もしくは波長の逆数、縦軸はノイズ信
号の強度を相対値で示す。図において、（ａ）は本発明
による垂直磁気記録媒体のノイズ特性、（ｂ）は比較用
媒体のノイズ特性を示す。媒体と磁気ヘッド間のスペー
シングが一定の状態で再生信号を比較したとき、磁気ヘ
ッドのスペーシングロスやギャップロスのために、不規
則磁区の寸法が小さいほどノイズ信号が小さくなる。図
から明らかなように、ほぼ全波長領域において本発明の
媒体は比較用媒体に比べてノイズ信号の強度が小さい。
特に比較用媒体は、波長０．２μｍ以上の長波長成分の
ノイズ信号が大きい。即ち比較用媒体は、大きな寸法の
不規則磁区が媒体に多く含まれ、媒体ノイズが大きいこ
とを示している。図４のノイズスペクトラムにおいて、
０．０６〜１０μｍの全波長成分を含むノイズを本発明
の媒体と比較用媒体とで比較すると、約１ｄＢ本発明の
媒体が低ノイズ特性を示した。The noise spectrum of a sample in which a perpendicular magnetization film was formed on the soft magnetic film, ie, the sample corresponding to FIG. 3D, was measured, and signals from the irregular magnetic domains were quantitatively compared. FIG. 4 shows the results. In FIG. 4, the horizontal axis represents the wavelength of the noise signal or the reciprocal of the wavelength, and the vertical axis represents the intensity of the noise signal as a relative value. In the figure, (a) shows the noise characteristic of the perpendicular magnetic recording medium according to the present invention, and (b) shows the noise characteristic of the comparative medium. When reproducing signals are compared in a state where the spacing between the medium and the magnetic head is constant, the noise signal decreases as the size of the irregular magnetic domain decreases due to the spacing loss and gap loss of the magnetic head. As is clear from the figure, the medium of the present invention has a smaller noise signal intensity in almost the entire wavelength region than the comparative medium.
In particular, the comparative medium has a large noise signal of a long wavelength component of a wavelength of 0.2 μm or more. That is, the medium for comparison contains a large amount of irregular magnetic domains of a large size in the medium, which means that medium noise is large. In the noise spectrum of FIG.
When the noise containing all wavelength components of 0.06 to 10 μm was compared between the medium of the present invention and the comparative medium, the medium of the present invention showed low noise characteristics at about 1 dB.
【００２７】ここでは、軟磁性膜１４としてＣｏ−１０
ａｔ％Ｔａ−５ａｔ％Ｚｒ非晶質合金膜を用いた例で説
明したが、他にＣｏ−Ｎｂ−Ｚｒ系非晶質合金、Ｃｏ−
Ｍｏ−Ｚｒ系非晶質合金、Ｃｏ−Ｗ−Ｚｒ系非晶質合
金、Ｃｏ−Ｔａ−Ｚｒ系非晶質合金、あるいはＣｏ−Ｎ
ｉ−Ｚｒ系非晶質合金を用いてもよい。これらの軟磁性
膜はいずれも非晶質構造の膜であることがＸ線回折法と
ＴＥＭ（透過電子顕微鏡）観察により確認された。ま
た、基板１１としてガラス基板を用いた例により説明し
たが、ガラス基板の他にＳｉディスク基板、ＮｉＰ被服
アルミニウム基板、カーボン基板、あるいは高分子基板
などを用いてもよい。更に、硬磁性膜１３としてＣｏ−
１８ａｔ％Ｃｒ−１４ａｔ％Ｐｔ−３ａｔ％Ｔａ薄膜を
用いた例で説明したが、Ｃｏを主成分としこれにＣｒ，
Ｐｔ，Ｔａ，Ｈｆ，Ｓｍの何れかを添加した他の合金を
用いてもよい。Here, Co-10 is used as the soft magnetic film 14.
Although an example using an at% Ta-5 at% Zr amorphous alloy film has been described, a Co-Nb-Zr-based amorphous alloy, Co-
Mo-Zr-based amorphous alloy, Co-W-Zr-based amorphous alloy, Co-Ta-Zr-based amorphous alloy, or Co-N
An i-Zr-based amorphous alloy may be used. It was confirmed by X-ray diffraction and TEM (transmission electron microscope) observation that these soft magnetic films were all films having an amorphous structure. Further, although an example using a glass substrate as the substrate 11 has been described, a Si disk substrate, a NiP-coated aluminum substrate, a carbon substrate, a polymer substrate, or the like may be used instead of the glass substrate. Further, as the hard magnetic film 13, Co-
Although the example using the 18 at% Cr-14 at% Pt-3 at% Ta thin film has been described, Co is used as a main component and Cr,
Another alloy to which any of Pt, Ta, Hf, and Sm is added may be used.
【００２８】〔実施例２〕図５は、本発明による垂直磁
気記録媒体の他の例を示す断面模式図である。図５に示
す垂直磁気記録媒体は、基板１１上に裏打磁性層１２、
垂直磁化膜の構造制御層１５、垂直磁化膜１６、及び保
護膜１７を積層して構成される。裏打磁性層１２は、高
保磁力の硬磁性膜１３と軟磁性膜１４とで構成される積
層構造を有する。軟磁性膜１４は、２種類の材料から構
成する。Embodiment 2 FIG. 5 is a schematic sectional view showing another example of a perpendicular magnetic recording medium according to the present invention. The perpendicular magnetic recording medium shown in FIG.
The structure is formed by laminating a structure control layer 15, a perpendicular magnetization film 16, and a protective film 17 of a perpendicular magnetization film. The backing magnetic layer 12 has a laminated structure composed of a hard magnetic film 13 having a high coercive force and a soft magnetic film 14. The soft magnetic film 14 is composed of two types of materials.
【００２９】即ち軟磁性膜１４は、下層に形成する多結
晶性の軟磁性膜１４−１と、この上に形成する非晶質の
軟磁性膜１４−２で構成する。多結晶性軟磁性膜１４−
１は、例えばＦｅ−Ａｌ−Ｓｉ−Ｍ合金（Ｍ：Ｃｒ，Ｔ
ｉ）、Ｆｅ−Ｔａ−Ｃ−Ｍ合金（Ｍ：Ａｌ，Ｃｒ）、Ｆ
ｅ−Ｈｆ−Ｃ−Ｍ合金（Ｍ：Ａｌ，Ｃｒ）、Ｆｅ−Ｔａ
−Ｎ−Ｍ合金（Ｍ：Ａｌ，Ｃｒ）、Ｎｉ−Ｆｅ−Ｍ合金
（Ｍ：Ｎｂ，Ｍｏ）から選ばれる。非晶質軟磁性膜１４
−２は、例えばＣｏ−Ｎｂ−Ｚｒ系非晶質合金、Ｃｏ−
Ｍｏ−Ｚｒ系非晶質合金、Ｃｏ−Ｗ−Ｚｒ系非晶質合
金、Ｃｏ−Ｔａ−Ｚｒ系非晶質合金、Ｃｏ−Ｎｉ−Ｚｒ
系非晶質合金から選ばれる。非晶質性の軟磁性膜１４−
２は、下層に形成した多結晶性の軟磁性膜１４−１の結
晶配向性の乱れ等によって軟磁性膜表面にミクロな磁区
が形成されるのを防止する役割がある。また下層の多結
晶性軟磁性膜１４−１は、硬磁性膜１３との磁気的相互
作用により上層の非晶質軟磁性膜１４−２の磁区固定効
果を促進する役割がある。本実施例では、軟磁性膜１４
−１としてＦｅ−８ａｔ％Ｔａ−１２ａｔ％Ｃ合金膜、
軟磁性膜１４−２としてＣｏ−４ａｔ％Ｔａ−９ａｔ％
Ｚｒ非晶質合金膜を用いた例で説明する。That is, the soft magnetic film 14 is composed of a polycrystalline soft magnetic film 14-1 formed below and an amorphous soft magnetic film 14-2 formed thereon. Polycrystalline soft magnetic film 14-
1 is, for example, an Fe-Al-Si-M alloy (M: Cr, T
i), Fe-Ta-CM alloy (M: Al, Cr), F
e-Hf-CM alloy (M: Al, Cr), Fe-Ta
-N-M alloy (M: Al, Cr) and Ni-Fe-M alloy (M: Nb, Mo). Amorphous soft magnetic film 14
-2 is, for example, a Co-Nb-Zr-based amorphous alloy, Co-
Mo-Zr-based amorphous alloy, Co-W-Zr-based amorphous alloy, Co-Ta-Zr-based amorphous alloy, Co-Ni-Zr
Selected from non-crystalline amorphous alloys. Amorphous soft magnetic film 14-
No. 2 has a role of preventing formation of micro magnetic domains on the surface of the soft magnetic film due to disorder of the crystal orientation of the polycrystalline soft magnetic film 14-1 formed as a lower layer. The lower polycrystalline soft magnetic film 14-1 has a role of promoting the magnetic domain fixing effect of the upper amorphous soft magnetic film 14-2 by magnetic interaction with the hard magnetic film 13. In this embodiment, the soft magnetic film 14
-1, Fe-8 at% Ta-12 at% C alloy film,
Co-4 at% Ta-9 at% as the soft magnetic film 14-2
An example using a Zr amorphous alloy film will be described.
【００３０】高真空ＤＣマグネトロンスパッタリング装
置により、図５に断面構造を示す垂直磁気記録媒体を作
製した。洗浄したガラス基板１１をスパッタリング装置
に設置し、続いて基板１１を約３００℃に加熱した。高
保磁力の硬磁性膜１３として磁化容易軸が基板面に垂直
方向に配向した試料を作製した。まず上記基板上に膜厚
３０ｎｍのＴｉ−１０ａｔ％Ｃｒ合金プリコート層を形
成した。このプリコート層の上に膜厚２０ｎｍの非磁性
Ｃｏ−３５ａｔ％Ｃｒ合金膜を介して膜厚２５ｎｍの磁
化容易軸が垂直配向したＣｏ−１６ａｔ％Ｃｒ−１４ａ
ｔ％Ｐｔ−３ａｔ％Ｔａ合金硬磁性膜１３を形成した。
硬磁性膜１３の膜面垂直方向の保磁力は３３００Ｏｅ、
角型比（ＳＱ＝残留磁化と飽和磁化の比）は０．８９で
あった。Using a high vacuum DC magnetron sputtering apparatus, a perpendicular magnetic recording medium having a sectional structure shown in FIG. 5 was produced. The washed glass substrate 11 was set in a sputtering apparatus, and subsequently, the substrate 11 was heated to about 300 ° C. As the hard magnetic film 13 having a high coercive force, a sample having an easy axis of magnetization oriented in a direction perpendicular to the substrate surface was prepared. First, a 30 nm-thick Ti-10 at% Cr alloy pre-coat layer was formed on the substrate. On this pre-coat layer, a Co-16 at% Cr-14a having a 25 nm-thick film whose easy axis of magnetization is vertically oriented via a non-magnetic Co-35 at% Cr alloy film having a thickness of 20 nm.
A t% Pt-3 at% Ta alloy hard magnetic film 13 was formed.
The coercive force of the hard magnetic film 13 in the direction perpendicular to the film surface is 3300 Oe,
The squareness ratio (SQ = the ratio of residual magnetization to saturation magnetization) was 0.89.
【００３１】続いて、この硬磁性膜１３の上に軟磁性膜
１４として前記の軟磁性膜１４−１と軟磁性膜１４−２
を順次形成した。軟磁性膜１４−１としてＦｅ−８ａｔ
％Ｔａ−１２ａｔ％Ｃ合金膜、軟磁性膜１４−２として
Ｃｏ−４ａｔ％Ｔａ−９ａｔ％Ｚｒ非晶質合金膜を用い
た。軟磁性膜１４は、磁気記録時に記録ヘッド磁束のリ
ターンパスとしての役割と信号再生時に垂直磁化膜から
の出力向上の役割をもつ。軟磁性膜１４−１と軟磁性膜
１４−２の膜厚の効果を調べるために、軟磁性膜１４の
全膜厚を４００ｎｍ一定として、軟磁性膜１４−２の膜
厚を０〜４００ｎｍの範囲で変化させた試料を作製し
た。軟磁性膜１４の保磁力は０．２〜０．８Ｏｅ、初透
磁率は２００〜８００であった。Subsequently, the soft magnetic film 14-1 and the soft magnetic film 14-2 are formed on the hard magnetic film 13 as soft magnetic films 14.
Were sequentially formed. Fe-8at as the soft magnetic film 14-1
A Co-4 at% Ta-9 at% Zr amorphous alloy film was used as the% Ta-12 at% C alloy film and the soft magnetic film 14-2. The soft magnetic film 14 has a role as a return path of the recording head magnetic flux at the time of magnetic recording and a role of improving the output from the perpendicular magnetization film at the time of signal reproduction. In order to examine the effect of the thickness of the soft magnetic film 14-1 and the soft magnetic film 14-2, the total thickness of the soft magnetic film 14 was set to 400 nm, and the thickness of the soft magnetic film 14-2 was set to 0 to 400 nm. Samples varied in the range were prepared. The coercive force of the soft magnetic film 14 was 0.2 to 0.8 Oe, and the initial magnetic permeability was 200 to 800.
【００３２】軟磁性膜１４の上に膜厚５ｎｍのＴｉ−１
０ａｔ％Ｃｒ合金からなる構造制御層１５を形成し、そ
の上に膜厚２０ｎｍの垂直磁化膜１６、膜厚５ｎｍの保
護膜１７を順次形成した。垂直磁化膜１６としてはＣｏ
−１８ａｔ％Ｃｒ−１２ａｔ％Ｐｔ−３ａｔ％Ｔａ合金
を用い、保護膜１７としてはカーボンを用いた。垂直磁
化膜１６の膜面垂直方向の保磁力は３１５０Ｏｅ、角型
比は０．９１であった。On the soft magnetic film 14, a 5-nm thick Ti-1
A structure control layer 15 made of a 0 at% Cr alloy was formed, and a 20 nm-thick perpendicular magnetic film 16 and a 5 nm-thick protective film 17 were sequentially formed thereon. As the perpendicular magnetization film 16, Co is used.
An alloy of -18 at% Cr-12 at% Pt-3 at% Ta was used, and carbon was used as the protective film 17. The coercive force of the perpendicular magnetization film 16 in the direction perpendicular to the film surface was 3150 Oe, and the squareness ratio was 0.91.
【００３３】比較のために、硬磁性膜１３の磁化容易軸
が基板面に平行に配向した試料を作製した。まず上記基
板１１上にプリコート層として膜厚５０ｎｍのＮｉ−５
０ａｔ％Ａｌ合金膜を形成し、この上に高保磁力の硬磁
性膜１３の結晶配向制御用の下地層として膜厚２０ｎｍ
のＣｒ膜を形成した。このＣｒ膜は＜１１０＞もしくは
＜１００＞方位に配向していた。この下地層の上に高保
磁力の硬磁性膜１３として膜厚２５ｎｍのＣｏ−１６ａ
ｔ％Ｃｒ−１４ａｔ％Ｐｔ−３ａｔ％Ｔａ合金薄膜を形
成した。この硬磁性膜１３は、ｈｃｐ構造のｃ軸が基板
面にほぼ平行に配向していた。硬磁性膜１３の面内方向
の保磁力は２８００Ｏｅ、角型比（ＳＱ＝残留磁化と飽
和磁化の比）は０．８１であった。For comparison, a sample was prepared in which the axis of easy magnetization of the hard magnetic film 13 was oriented parallel to the substrate surface. First, a 50 nm-thick Ni-5 film was formed on the substrate 11 as a precoat layer.
A 0 at% Al alloy film is formed, and a 20 nm-thick film is formed thereon as an underlayer for controlling the crystal orientation of the hard magnetic film 13 having a high coercive force.
Was formed. This Cr film was oriented in the <110> or <100> direction. On this underlayer, Co-16a having a thickness of 25 nm was formed as a hard magnetic film 13 having a high coercive force.
A t% Cr-14at% Pt-3at% Ta alloy thin film was formed. In the hard magnetic film 13, the c-axis of the hcp structure was oriented substantially parallel to the substrate surface. The coercive force in the in-plane direction of the hard magnetic film 13 was 2800 Oe, and the squareness ratio (SQ = the ratio of residual magnetization to saturation magnetization) was 0.81.
【００３４】続いて、この硬磁性膜１３の上に軟磁性膜
１４を形成した。軟磁性膜１４は、硬磁性膜１３の上に
軟磁性膜１４−１と軟磁性膜１４−２を順次形成してな
る。軟磁性膜１４−１としてＦｅ−８ａｔ％Ｔａ−１２
ａｔ％Ｃ合金膜、軟磁性膜１４−２としてＣｏ−４ａｔ
％Ｔａ−９ａｔ％Ｚｒ非晶質合金膜を用いた。軟磁性膜
１４−１と軟磁性膜１４−２の膜厚の効果を調べるため
に、軟磁性膜１４の全膜厚を４００ｎｍ一定として、軟
磁性膜１４−２の膜厚を０〜４００ｎｍの範囲で変化し
た試料を作製した。軟磁性膜１４の保磁力は０．２〜
０．８Ｏｅ、初透磁率は２００〜８００であった。軟磁
性膜１４の上に膜厚５ｎｍのＴｉ−１０ａｔ％Ｃｒ合金
からなる構造制御層１５を形成し、その上に膜厚２０ｎ
ｍの垂直磁化膜１６、膜厚５ｎｍの保護膜１７を順次形
成した。垂直磁化膜１６としてはＣｏ−１８ａｔ％Ｃｒ
−１２ａｔ％Ｐｔ−３ａｔ％Ｔａ合金を用い、保護膜１
７としてはカーボンを用いた。垂直磁化膜１６の膜面垂
直方向の保磁力は３１００Ｏｅ、角型比は０．９０であ
った。Subsequently, a soft magnetic film 14 was formed on the hard magnetic film 13. The soft magnetic film 14 is formed by sequentially forming a soft magnetic film 14-1 and a soft magnetic film 14-2 on the hard magnetic film 13. Fe-8 at% Ta-12 as the soft magnetic film 14-1
Co-4at as at% C alloy film and soft magnetic film 14-2
% Ta-9 at% Zr amorphous alloy film was used. In order to examine the effect of the thickness of the soft magnetic film 14-1 and the soft magnetic film 14-2, the total thickness of the soft magnetic film 14 was set to 400 nm, and the thickness of the soft magnetic film 14-2 was set to 0 to 400 nm. Samples with varying ranges were made. The coercive force of the soft magnetic film 14 is 0.2 to
0.8 Oe, and the initial magnetic permeability was 200 to 800. A structure control layer 15 made of a Ti-10 at% Cr alloy having a thickness of 5 nm is formed on the soft magnetic film 14, and a 20 nm film thickness is formed thereon.
An m-perpendicular film 16 and a 5 nm-thick protective film 17 were sequentially formed. Co-18 at% Cr for the perpendicular magnetization film 16
Protective film 1 using -12 at% Pt-3 at% Ta alloy
7 was carbon. The coercive force of the perpendicular magnetization film 16 in the direction perpendicular to the film surface was 3100 Oe, and the squareness ratio was 0.90.
【００３５】軟磁性膜１４の表面磁区構造に及ぼす硬磁
性膜１３の結晶配向の影響を、残留磁化状態における磁
区構造観察により比較した。図６に、磁気力顕微鏡で観
察した磁区構造を示す。図６において、（ａ）の列は硬
磁性膜１３の磁化容易軸が膜面垂直方向に配向した本発
明による媒体の軸構造を示し、（ｂ）の列は硬磁性膜１
３の磁化容易軸が膜面平行方向に配向した比較用媒体の
磁区構造を示す。また、同図において（イ）、（ロ）
は、図５に矢印で示したように、（イ）は硬磁性膜１３
表面の磁区構造、（ロ）は軟磁性膜１４−２表面の磁区
構造である。ここで（ロ）は、一例として軟磁性膜１４
−１の膜厚を３６０ｎｍとし、軟磁性膜１４−２の膜厚
を４０ｎｍとしたときの結果を示す。The effect of the crystal orientation of the hard magnetic film 13 on the surface magnetic domain structure of the soft magnetic film 14 was compared by observing the magnetic domain structure in a remanent magnetization state. FIG. 6 shows a magnetic domain structure observed with a magnetic force microscope. In FIG. 6, (a) shows the axial structure of the medium according to the present invention in which the easy axis of magnetization of the hard magnetic film 13 is oriented in the direction perpendicular to the film surface, and (b) shows the hard magnetic film 1.
3 shows the magnetic domain structure of a comparative medium in which the easy axis of magnetization 3 is oriented in the direction parallel to the film surface. In the same figure, (a), (b)
(A) shows the hard magnetic film 13 as shown by the arrow in FIG.
(B) is a magnetic domain structure on the surface of the soft magnetic film 14-2. Here, (b) shows the soft magnetic film 14 as an example.
The results when the film thickness of -1 is 360 nm and the film thickness of the soft magnetic film 14-2 is 40 nm are shown.
【００３６】この磁区構造において、明暗のコントラス
トで磁区構造の乱れが示されている。図６において、黒
いコントラストで観察される領域が媒体ノイズの原因と
なる不規則構造の磁区であり、不規則構造磁区の寸法が
小さいほど、また磁区から発生する信号が小さいほど、
ノイズが小さい。垂直配向した硬磁性膜の上に軟磁性膜
を形成した本発明の媒体（ａ）では、図６（ａ）に示す
ように、硬磁性膜表面の不規則構造磁区の寸法が小さ
く、更に軟磁性膜表面の磁区構造の乱れも少ない。一
方、面内配向した硬磁性膜の上に軟磁性膜を形成した比
較用媒体（ｂ）では、硬磁性膜表面の不規則構造磁区の
寸法が大きく、更に軟磁性膜表面に縞状の磁区が形成さ
れ大きな磁区構造の乱れが観察される。これは磁気ヘッ
ドで再生したとき特に長波長成分のノイズ信号の源とな
る。In this magnetic domain structure, disturbance of the magnetic domain structure is shown by light and dark contrast. In FIG. 6, the region observed with black contrast is a magnetic domain having an irregular structure that causes medium noise, and the smaller the size of the irregular structure magnetic domain and the smaller the signal generated from the magnetic domain,
Noise is small. In the medium (a) of the present invention in which a soft magnetic film is formed on a vertically oriented hard magnetic film, as shown in FIG. 6A, the size of the irregular magnetic domains on the surface of the hard magnetic film is small, and There is little disturbance of the magnetic domain structure on the surface of the magnetic film. On the other hand, in the comparative medium (b) in which the soft magnetic film is formed on the in-plane oriented hard magnetic film, the size of the irregular magnetic domains on the surface of the hard magnetic film is large, and the magnetic domains having stripes are formed on the surface of the soft magnetic film. Are formed and large disturbance of the magnetic domain structure is observed. This becomes a source of a noise signal particularly of a long wavelength component when reproduced by a magnetic head.
【００３７】図７に、図５に断面構造を示した本発明に
よる垂直磁気記録媒体と比較用媒体において、軟磁性膜
１４−２の膜厚と媒体ノイズの関係を比較して示す。前
記垂直磁気記録媒体に単磁極ヘッド（トラック幅１．２
μｍ、磁極の飽和磁束密度１．６テスラ）により垂直磁
気記録を行い、ＧＭＲヘッド（巨大磁気抵抗効果型ヘッ
ド、トラック幅０．８μｍ、ギャップ長０．１２μｍ）
で再生した。磁気記録再生時の媒体・ヘッド間のスペー
シングは約１６ｎｍとした。記録電流とオーバーライト
特性（２５４ｋＦＣＩの上に４５ｋＦＣＩの信号を記
録）の関係を測定し、オーバーライトＳ／Ｎが３５ｄＢ
以上が確保される記録電流で磁気記録を行った。磁気記
録の後、媒体ノイズは前記ＧＭＲヘッドを用いて０〜４
０ＭＨｚの範囲のノイズスペクトルを測定し、この範囲
の積算強度を測定した。図７の媒体ノイズは相対値で示
した。FIG. 7 shows the relationship between the thickness of the soft magnetic film 14-2 and the medium noise in the perpendicular magnetic recording medium according to the present invention and the comparative medium whose sectional structures are shown in FIG. A single-pole head (with a track width of 1.2)
perpendicular magnetic recording with a magnetic pole saturation magnetic flux density of 1.6 Tesla) and a GMR head (giant magnetoresistive head, track width 0.8 μm, gap length 0.12 μm)
Played with. The spacing between the medium and the head during magnetic recording / reproducing was set to about 16 nm. The relationship between the recording current and the overwrite characteristics (recording a signal of 45 kFCI on 254 kFCI) was measured, and the overwrite S / N was 35 dB.
Magnetic recording was performed with a recording current that ensures the above. After the magnetic recording, the medium noise was reduced to 0 to 4 using the GMR head.
A noise spectrum in the range of 0 MHz was measured, and the integrated intensity in this range was measured. The medium noise in FIG. 7 is shown as a relative value.
【００３８】図７から明らかなように、多結晶性の軟磁
性膜１４−１の上に非晶質性の軟磁性膜１４−２を形成
することにより媒体ノイズが低減できる。さらに硬磁性
膜１３として磁化容易軸が面内配向した比較用媒体に比
べて、硬磁性膜１３の磁化容易軸が膜面に垂直配向した
本発明の媒体はいずれの膜厚においても優れた低ノイズ
特性が得られた。As is apparent from FIG. 7, the medium noise can be reduced by forming the amorphous soft magnetic film 14-2 on the polycrystalline soft magnetic film 14-1. Further, as compared with the comparative medium in which the easy axis of magnetization is in-plane oriented as the hard magnetic film 13, the medium of the present invention in which the easy axis of hard magnetic film 13 is oriented perpendicular to the film surface is excellent in any thickness. Noise characteristics were obtained.
【００３９】図８に、軟磁性膜１４−１の膜厚を３６０
ｎｍ、軟磁性膜１４−２の膜厚を４０ｎｍとした前記本
発明の媒体と比較用媒体について、直流消去後の媒体ノ
イズをスペクトラムアナライザ測定した結果を示す。比
較用媒体は、特に２５ＭＨｚ以下の長波長成分のノイズ
信号強度が本発明の媒体に比べて大きい。図６の軟磁性
膜表面の磁区構造に示したように、比較用媒体の軟磁性
膜の表面には縞状の磁区構造が形成されており、このよ
うな軟磁性膜の磁区の乱れが上層に形成した垂直磁化膜
の磁区構造に影響し長波長成分の媒体ノイズを増加させ
たと考えられる。FIG. 8 shows that the thickness of the soft magnetic film 14-1 is 360
5 shows the results of spectrum analyzer measurement of medium noise after DC erasing for the medium of the present invention and the comparative medium in which the thickness of the soft magnetic film 14-2 was 40 nm. The medium for comparison has a larger noise signal intensity especially for a long wavelength component of 25 MHz or less than the medium of the present invention. As shown in the magnetic domain structure on the surface of the soft magnetic film in FIG. 6, a magnetic domain structure in the form of stripes is formed on the surface of the soft magnetic film of the comparative medium. It is considered that the influence of the magnetic domain structure of the perpendicular magnetization film formed in the above-mentioned method increases the medium noise of the long wavelength component.
【００４０】〔実施例３〕図９は、本発明による磁気記
憶装置の概略図である。磁気記憶装置は、磁気ディスク
３１、磁気ディスク３１を回転駆動するモータ、記録再
生用の磁気ヘッド３２、磁気ヘッド３２を支持するサス
ペンジョン３３、磁気ヘッド３２を磁気ディスクに対し
て相対的に駆動するアクチュエータ３４、ボイスコイル
モータ３５、記録信号や再生信号を処理する記録再生回
路３６、磁気ヘッドの位置決め回路３７、インターフェ
ース制御回路３８などで構成される。磁気ディスク３１
は上記実施例１あるいは実施例２にて説明した垂直磁気
記録媒体からなり、保護膜上には潤滑膜が被覆されてい
る。磁気ヘッド３２は、スライダーの上に設けられた磁
気記録用ヘッド及び信号再生用の磁気抵抗効果型、巨大
磁気抵抗効果型もしくはスピンバルブ型素子あるいは磁
気トンネル型素子からなる再生用ヘッドで構成される。
記録信号再生用の磁気ヘッドのギャップ長は、高分解能
の再生信号を得るために０．２５μｍ以下とし、望まし
くは０．０８〜０．１５μｍとする。磁気記録用のヘッ
ドは、単磁極型ヘッドもしくはリング型ヘッドのいずれ
を用いても良い。再生用ヘッドのトラック幅は、記録用
ヘッド磁極のトラック幅より狭くし、記録トラック両端
部から生じる再生ノイズを低減する。Embodiment 3 FIG. 9 is a schematic diagram of a magnetic storage device according to the present invention. The magnetic storage device includes a magnetic disk 31, a motor for rotating the magnetic disk 31, a magnetic head 32 for recording and reproduction, a suspension 33 for supporting the magnetic head 32, and an actuator for driving the magnetic head 32 relative to the magnetic disk. 34, a voice coil motor 35, a recording / reproducing circuit 36 for processing recording signals and reproducing signals, a magnetic head positioning circuit 37, an interface control circuit 38, and the like. Magnetic disk 31
Is composed of the perpendicular magnetic recording medium described in the first embodiment or the second embodiment, and the protective film is covered with a lubricating film. The magnetic head 32 includes a magnetic recording head provided on a slider and a reproducing head composed of a magnetoresistive, giant magnetoresistive, spin-valve or magnetic tunnel element for reproducing signals. .
The gap length of the magnetic head for reproducing the recording signal is set to 0.25 μm or less, preferably 0.08 to 0.15 μm in order to obtain a high-resolution reproduction signal. As a magnetic recording head, either a single pole type head or a ring type head may be used. The track width of the reproducing head is made narrower than the track width of the recording head magnetic pole to reduce reproduction noise generated from both ends of the recording track.
【００４１】磁気ヘッド３２は、サスペンジョン３３に
よって支持される。本装置を用いて、前記実施例１，２
で説明した垂直磁気記録媒体の媒体ノイズ特性や記録再
生特性の評価を行った。本発明の垂直磁気記録媒体によ
り、出力半減線記録密度Ｄ５ ０：２８０ｋＦＣＩ、この
密度における媒体ノイズ：８μＶｒｍｓ／μＶｐｐ、エ
ラーレート：１０−６以下の高密度特性が得られた。前
記実施例では、垂直磁化膜、構造制御層、軟磁性膜、硬
磁性膜の一例を挙げて内容の説明を行ったが、実施例に
記述した他の材料のいずれを組み合わせて用いても同様
の効果が得られることは言うまでもない。The magnetic head 32 is supported by the suspension 33. Using this apparatus, the first and second embodiments were used.
The medium noise characteristics and the recording / reproducing characteristics of the perpendicular magnetic recording medium described in the above section were evaluated. The perpendicular magnetic recording medium of the present invention, the output half-line recording density D 5 0: 280kFCI, medium in the density Noise: 8μVrms / μVpp, Error rate: 10 -6 or less dense characteristic was obtained. In the above-described embodiment, the description has been made by giving examples of the perpendicular magnetization film, the structure control layer, the soft magnetic film, and the hard magnetic film. However, the same applies when any of the other materials described in the embodiment is used in combination. Needless to say, the effect is obtained.
【００４２】[0042]
【発明の効果】本発明によると、媒体ノイズの原因とな
る軟磁性膜表面の縞状磁区の形成を抑止して垂直磁化膜
媒表面における不規則磁区の寸法の微細化を可能とし、
媒体ノイズの小さい記録磁化の安定性に優れた超高密度
磁気記録に好適な垂直磁気記録媒体を得ることができ
る。According to the present invention, the formation of striped magnetic domains on the surface of the soft magnetic film which causes medium noise is suppressed, and the size of the irregular magnetic domains on the surface of the perpendicular magnetic film medium can be reduced.
It is possible to obtain a perpendicular magnetic recording medium suitable for ultra-high-density magnetic recording which is excellent in stability of recording magnetization with small medium noise.
【図１】本発明による垂直磁気記録媒体の基本構造の一
例を示す断面模式図。FIG. 1 is a schematic sectional view showing an example of a basic structure of a perpendicular magnetic recording medium according to the present invention.
【図２】実施例１の垂直磁気記録媒体の説明図。FIG. 2 is an explanatory diagram of a perpendicular magnetic recording medium according to the first embodiment.
【図３】磁区構造の比較説明図。FIG. 3 is a comparative explanatory view of a magnetic domain structure.
【図４】本発明の媒体と比較用媒体のノイズスペクトル
の比較説明図。FIG. 4 is a comparative explanatory diagram of noise spectra of the medium of the present invention and a comparative medium.
【図５】実施例２の垂直磁気記録媒体の説明図。FIG. 5 is an explanatory diagram of a perpendicular magnetic recording medium according to a second embodiment.
【図６】磁区構造の比較説明図。FIG. 6 is a comparative explanatory view of a magnetic domain structure.
【図７】軟磁性膜厚と媒体ノイズの関係の説明図。FIG. 7 is an explanatory diagram of a relationship between a soft magnetic film thickness and medium noise.
【図８】本発明の媒体と比較用媒体のノイズスペクトラ
ムの説明図。FIG. 8 is an explanatory diagram of a noise spectrum of a medium of the present invention and a noise spectrum of a comparative medium.
【図９】磁気記憶装置の説明図。FIG. 9 is an explanatory diagram of a magnetic storage device.
１１：基板、１２：裏打磁性層、１３：硬磁性膜、１
４：軟磁性膜、１４−１：多結晶軟磁性膜、１４−２：
非晶質軟磁性膜、１５：構造制御層、１６：垂直磁化
膜、１７：保護層、３１：磁気ディスク、３２：磁気ヘ
ッド、３３：サスペンジョン、３４：アクチュエータ、
３５：ボイスコイルモータ、３６：記録再生回路、３
７：位置決め回路、３８：インターフェース制御回路。11: substrate, 12: backing magnetic layer, 13: hard magnetic film, 1
4: soft magnetic film, 14-1: polycrystalline soft magnetic film, 14-2:
Amorphous soft magnetic film, 15: structure control layer, 16: perpendicular magnetization film, 17: protective layer, 31: magnetic disk, 32: magnetic head, 33: suspension, 34: actuator,
35: voice coil motor, 36: recording / reproducing circuit, 3
7: Positioning circuit, 38: Interface control circuit.
フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｈ０１Ｆ 41/18 Ｈ０１Ｆ 41/18 (72)発明者 二本 正昭 東京都国分寺市東恋ヶ窪一丁目280番地 株式会社日立製作所中央研究所内 (72)発明者 菊川 敦 東京都国分寺市東恋ヶ窪一丁目280番地 株式会社日立製作所中央研究所内 Ｆターム(参考） 5D006 BB01 BB07 BB08 CA05 5E049 AA01 AA04 AA07 AA09 AC01 BA12 CB02 GC01 Continued on the front page (51) Int.Cl. 7 Identification code FI Theme coat II (Reference) H01F 41/18 H01F 41/18 (72) Inventor Masaaki Nihon 1-280 Higashi-Koigabo, Kokubunji-shi, Tokyo Hitachi, Ltd. In the laboratory (72) Inventor Atsushi Kikukawa 1-280 Higashi-Koigabo, Kokubunji-shi, Tokyo F-term in the Central Research Laboratory, Hitachi, Ltd.F-term (reference)
Claims (6)
を設けた垂直磁気記録媒体において、前記裏打磁性層は
基板に近い側に形成した磁化容易軸が垂直配向した硬磁
性膜と、前記硬磁性膜の上に形成した軟磁性膜とを含む
ことを特徴とする垂直磁気記録媒体。1. A perpendicular magnetic recording medium in which a perpendicular magnetic film is provided on a substrate via a backing magnetic layer, wherein the backing magnetic layer is formed on a side close to the substrate and has a hard magnetic film whose easy axis of magnetization is vertically oriented; And a soft magnetic film formed on the hard magnetic film.
て、前記硬磁性膜の保磁力は１ｋＯｅ以上であり、前記
軟磁性膜は保磁力が１Ｏｅ以下の非晶質軟磁性膜である
ことを特徴とする垂直磁気記録媒体。2. The perpendicular magnetic recording medium according to claim 1, wherein the coercive force of the hard magnetic film is 1 kOe or more, and the soft magnetic film is an amorphous soft magnetic film having a coercive force of 1 Oe or less. Characteristic perpendicular magnetic recording medium.
て、前記硬磁性膜の保磁力は１ｋＯｅ以上であり、前記
軟磁性膜は多結晶性軟磁性膜上に非晶質軟磁性膜が形成
された積層構造を有し保磁力が１Ｏｅ以下であることを
特徴とする垂直磁気記録媒体。3. The perpendicular magnetic recording medium according to claim 1, wherein the coercive force of the hard magnetic film is 1 kOe or more, and the soft magnetic film is formed by forming an amorphous soft magnetic film on a polycrystalline soft magnetic film. A perpendicular magnetic recording medium having a laminated structure and a coercive force of 1 Oe or less.
において、前記非晶質軟磁性膜はＣｏ−Ｎｂ−Ｚｒ系非
晶質合金、Ｃｏ−Ｍｏ−Ｚｒ系非晶質合金、Ｃｏ−Ｗ−
Ｚｒ系非晶質合金、Ｃｏ−Ｔａ−Ｚｒ系非晶質合金、Ｃ
ｏ−Ｎｉ−Ｚｒ系非晶質合金から選ばれる何れかの材料
で構成され、前記多結晶性軟磁性膜はＦｅ−Ａｌ−Ｓｉ
−Ｍ合金（Ｍ：Ｃｒ，Ｔｉ）、Ｆｅ−Ｔａ−Ｃ−Ｍ合金
（Ｍ：Ａｌ，Ｃｒ）、Ｆｅ−Ｈｆ−Ｃ−Ｍ合金（Ｍ：Ａ
ｌ，Ｃｒ）、Ｆｅ−Ｔａ−Ｎ−Ｍ合金（Ｍ：Ａｌ，Ｃ
ｒ）、Ｎｉ−Ｆｅ−Ｍ合金（Ｍ：Ｎｂ，Ｍｏ）から選ば
れる何れかの材料で構成され、前記硬磁性膜はＣｏを主
成分としこれにＣｒ，Ｐｔ，Ｔａ，Ｈｆ，Ｓｍの何れか
を添加した合金からなることを特徴とする垂直磁気記録
媒体。4. The perpendicular magnetic recording medium according to claim 2, wherein the amorphous soft magnetic film is a Co—Nb—Zr based amorphous alloy, a Co—Mo—Zr based amorphous alloy, W-
Zr-based amorphous alloy, Co-Ta-Zr-based amorphous alloy, C
The polycrystalline soft magnetic film is made of any material selected from an o-Ni-Zr-based amorphous alloy, and the polycrystalline soft magnetic film is made of Fe-Al-Si.
-M alloy (M: Cr, Ti), Fe-Ta-CM alloy (M: Al, Cr), Fe-Hf-CM alloy (M: A
1, Cr), Fe-Ta-NM alloy (M: Al, C
r), any material selected from Ni-Fe-M alloys (M: Nb, Mo), and the hard magnetic film is mainly composed of Co and contains any of Cr, Pt, Ta, Hf, and Sm. A perpendicular magnetic recording medium comprising an alloy to which is added.
磁気記録媒体において、前記裏打磁性層と前記垂直磁化
膜の間に膜厚１〜１０ｎｍの非磁性の構造制御層を含む
ことを特徴とする垂直磁気記録媒体。5. The perpendicular magnetic recording medium according to claim 1, further comprising a nonmagnetic structure control layer having a thickness of 1 to 10 nm between said backing magnetic layer and said perpendicular magnetization film. A perpendicular magnetic recording medium characterized by the above-mentioned.
動する駆動手段と、記録部と再生部とを備える磁気ヘッ
ドと、前記磁気ヘッドを前記磁気記録媒体に対して相対
的に移動させる磁気ヘッド駆動手段と、磁気ヘッドの記
録信号及び再生信号を処理する信号処理手段とを備える
磁気記憶装置において、 前記磁気記録媒体として請求項１〜５のいずれか１項記
載の垂直磁気記録媒体を用いたことを特徴とする磁気記
憶装置。6. A magnetic head including a magnetic recording medium, a driving unit for driving the magnetic recording medium, a recording unit and a reproducing unit, and a magnetic head for moving the magnetic head relative to the magnetic recording medium. 6. A magnetic storage device comprising: a head driving unit; and a signal processing unit for processing a recording signal and a reproduction signal of a magnetic head, wherein the perpendicular magnetic recording medium according to claim 1 is used as the magnetic recording medium. A magnetic storage device.
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|---|---|---|---|
| JP2000158925A JP3340420B2 (en) | 2000-05-29 | 2000-05-29 | Perpendicular magnetic recording medium and magnetic storage device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000158925A JP3340420B2 (en) | 2000-05-29 | 2000-05-29 | Perpendicular magnetic recording medium and magnetic storage device |
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| Publication Number | Publication Date |
|---|---|
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008071406A (en) * | 2006-09-13 | 2008-03-27 | Fuji Electric Device Technology Co Ltd | Vertical magnetic recording medium |
| WO2012026405A1 (en) * | 2010-08-24 | 2012-03-01 | 山陽特殊製鋼株式会社 | Soft magnetic alloy for magnetic recording medium, sputtering target material, and magnetic recording medium |
| US11908500B2 (en) | 2006-06-17 | 2024-02-20 | Dieter Suess | Multilayer exchange spring recording media |
-
2000
- 2000-05-29 JP JP2000158925A patent/JP3340420B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11908500B2 (en) | 2006-06-17 | 2024-02-20 | Dieter Suess | Multilayer exchange spring recording media |
| JP2008071406A (en) * | 2006-09-13 | 2008-03-27 | Fuji Electric Device Technology Co Ltd | Vertical magnetic recording medium |
| WO2012026405A1 (en) * | 2010-08-24 | 2012-03-01 | 山陽特殊製鋼株式会社 | Soft magnetic alloy for magnetic recording medium, sputtering target material, and magnetic recording medium |
| JP2012048767A (en) * | 2010-08-24 | 2012-03-08 | Sanyo Special Steel Co Ltd | Soft magnetic alloy for magnetic recording medium, sputtering target material and magnetic recording medium |
| US9208812B2 (en) | 2010-08-24 | 2015-12-08 | Sanyo Special Steel Co., Ltd. | Soft magnetic alloy for magnetic recording medium, sputtering target material, and magnetic recording medium |
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