JPS60239916A - Vertical magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium which has a large S/N ratio and large reproduced output and is suitable for high-density recording and reproduction by forming a laminated vertically magnetizable film consisting of an upper Co-Cr film having a high concn. of Cr and a lower Co-Cr film having a low concn. of Cr on a non-magnetic substrate. CONSTITUTION:A high-permeability layer 2 consisting of ''Permalloy(R)'', etc. is formed by a sputtering method on a non-magnetic substrate 1 consisting of alumite, etc. via a thin Ti film 3 in order to improve the adhesion between the magnetic layer and the substrate. A Ti film 5 is formed on the layer 2 in order to improve the vertical orientability of the lower Co-Cr film and thereafter the lower Co-Cr film 4 having <=18% concn. of Cr is formed thereon. The upper Co-Cr film 6 contg. >=20at% concn. of Cr is formed on the film 4. Since the film 6 has a high concn. of Cr in the above-mentioned way, the grain size is decreased and the noise is decreased. The film 4 has high saturation magnetization and larger reproduced output. The recording medium provided with the good S/N and excellent reproduced output by the presence of both layers is obtd.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 この発明は、垂直磁気記録媒体に係り、さらに詳細には
Ｓ／Ｎの良好なＣｏ　−Ｃｒ垂直磁化膜構造を有する垂
直磁気記録媒体に関するものである。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a perpendicular magnetic recording medium, and more particularly to a perpendicular magnetic recording medium having a Co--Cr perpendicular magnetization film structure with a good S/N ratio. It is.

〔従来の技術〕[Conventional technology]

最近、垂直磁気記録方式は、高密度の記録／再生が可能
であることから急速に研究開発が進められている。この
記録方式を実現するためには、垂直に磁化し易く、かつ
その磁化を安定に保持できる垂直磁気異方性をもった記
録媒体が必要である。Recently, perpendicular magnetic recording has been rapidly researched and developed because it enables high-density recording/reproduction. In order to realize this recording method, a recording medium that is easily magnetized perpendicularly and has perpendicular magnetic anisotropy that can stably maintain the magnetization is required.

この垂直磁気記録媒体として、コバルト（ＣＯ）を母相
とし、その結晶磁気異方性を利用し、ｈｃｐ構造のＣ軸
を垂直配向させたＣｏ−Ｍ系の薄膜媒体が現在量も広く
研究開発されており、これまでにスパッタ法で作ったＣ
ｏ−Ｃｒ合金膜が最も強い垂直磁気異方性を示すことが
明らかになっている。As perpendicular magnetic recording media, Co-M thin film media, which have cobalt (CO) as a parent phase and utilize its crystal magnetic anisotropy to vertically align the C-axis of the hcp structure, are currently being widely researched and developed. C made by sputtering method so far.
It has been revealed that the o-Cr alloy film exhibits the strongest perpendicular magnetic anisotropy.

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

従来の垂直磁気記録媒体は、均一な濃度のＣｏ　−Ｃｒ
膜を記録層として用いている。このような媒体では、Ｃ
ｒ濃度の低いＣｏ　−Ｃｒ膜を用いると飽和磁化が高く
なって再生出力は大きくなるが、粒径が大きくなってノ
イズが増し、逆にＣｒ濃度を高くすると粒径は小さくな
ってノイズは小さくなるが、飽和磁化も低下して再生出
力も小さくなる欠点がある。Conventional perpendicular magnetic recording media have a uniform concentration of Co-Cr.
A film is used as the recording layer. In such media, C
If a Co-Cr film with a low r concentration is used, the saturation magnetization will be high and the reproduction output will be large, but the grain size will become large and noise will increase.On the other hand, if the Cr concentration is increased, the grain size will become small and the noise will be small. However, there is a drawback that the saturation magnetization also decreases and the reproduction output also decreases.

〔問題点を解決するための手段〕[Means for solving problems]

この発明は、Ｓ／Ｈの良好な新しい垂直磁化Ｃ。 This invention is a new perpendicular magnetization C with good S/H.

−Ｃｒ膜を有する磁気記録媒体を提供しようとするもの
であり、その垂直磁化Ｃｏ　−Ｃｒ膜は、Ｃｒ濃度の高
い上層のＣｏ　−Ｃｒ膜とＣｒ濃度の低い下層のＣｏ　
−Ｃｒ膜との２層膜構造よりなることを特徴とするもの
である。The purpose of the present invention is to provide a magnetic recording medium having a perpendicularly magnetized Co-Cr film, which consists of an upper Co-Cr film with a high Cr concentration and a lower Co-Cr film with a low Cr concentration.
- It is characterized by having a two-layer film structure with a Cr film.

〔作用〕[Effect]

上記垂直磁化Ｃｏ　−Ｃｒ膜は、磁気ヘッドと直接相対
する上層のＣｏ−Ｃｒ膜が小粒径であるために媒体ノイ
ズを小さくでき、また下層のＣｏ　−Ｃｒ膜が高飽和磁
化を有するため磁気ヘッドによる再生出力を大きくし、
結果としてＳ／Ｎの優れた実用的な磁気記録媒体を供す
ることができる。The perpendicularly magnetized Co-Cr film can reduce medium noise because the upper Co-Cr film that directly faces the magnetic head has a small grain size, and the lower Co-Cr film has high saturation magnetization. Increase the playback output from the head,
As a result, a practical magnetic recording medium with excellent S/N ratio can be provided.

〔実施例〕〔Example〕

以下、この発明の一実施例について図面を参照して詳細
に説明する。Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

第１図はかかる実施例の媒体構造の要部断面図を示し、
この図において１はアルマイト基板、２はスパッタ法に
より成膜された膜厚１μｍのパーマロイから成る高透磁
率磁性層、３は高透磁率磁性層２とアルマイト基板１と
の密着性を高めるためのチタニウム（Ｔｉ）から成る２
００人の非磁性膜、４はスパッタ法により成膜された膜
厚０．３μｍのＣｒａ度１８ａｔ％の下層となるＣｏ　
−Ｃｒ膜で、飽和磁化は５００　ｅｍｕ／ｃｃ、粒径は
第２図のＣｏ　−Ｃｒ膜厚と粒径との関係図に示すよう
に１１００人を有する。また、５は下層Ｃｏ　−Ｃｒ膜
４の垂直配向性を高めるための２００人のＴｉ膜、６は
スパッタ法により成膜された膜厚０．２μｍのＣｒ濃度
２０ａ　ｔ％の上層となるＣｏ　−Ｃｒ膜であり、飽和
磁化は３５０　ｅｍｕ／ｃｃ、粒径は第２図に示すよう
に４５０人を有する。FIG. 1 shows a sectional view of a main part of the medium structure of such an embodiment,
In this figure, 1 is an alumite substrate, 2 is a high permeability magnetic layer made of permalloy with a film thickness of 1 μm formed by sputtering, and 3 is a high permeability magnetic layer made of permalloy with a film thickness of 1 μm formed by sputtering. Made of titanium (Ti)2
00's non-magnetic film, 4 is Co as the lower layer with a film thickness of 0.3 μm and a Cra degree of 18 at% formed by sputtering.
The -Cr film has a saturation magnetization of 500 emu/cc and a grain size of 1100 as shown in the relation diagram between Co--Cr film thickness and grain size in FIG. In addition, 5 is a 200-layer Ti film for improving the vertical orientation of the lower Co-Cr film 4, and 6 is a Co-200 layer formed by a sputtering method with a thickness of 0.2 μm and a Cr concentration of 20 at%. It is a Cr film, has a saturation magnetization of 350 emu/cc, and a grain size of 450 emu/cc as shown in FIG.

このような本実施例の二層Ｃｏ　−Ｃｒ膜構造を持つ磁
気記録媒体では、上層に粒径の小さいＣｏ　−Ｃｒ膜６
を有するので媒体ノイズが小さくなり、かつ下層に飽和
磁化の高いＣｏ　−Ｃｒ膜４を有するので再生出力が大
きくなる。In the magnetic recording medium having the two-layer Co--Cr film structure of this embodiment, the Co--Cr film 6 with small grain size is provided as an upper layer.
Since it has this, the medium noise is reduced, and since it has the Co--Cr film 4 with high saturation magnetization in the lower layer, the reproduction output becomes large.

なお、上記実施例では非磁性基板１にアルマイト材を使
用したが、ガラスやセラミックス相も適用可能であり、
また上層、下層のＣｏ−Ｃｒ膜６．４におけるＣｒ含有
濃度の比率も適宜に選択できるものである。In addition, although alumite material was used for the non-magnetic substrate 1 in the above embodiment, glass or ceramic phase may also be applied.
Further, the ratio of the Cr content concentration in the upper and lower Co--Cr films 6.4 can be selected as appropriate.

〔発明の効果〕〔Effect of the invention〕

以上の説明から明らかなように本発明によれば、Ｓ／Ｎ
の良好な垂直磁気記録媒体を得ることができるので、垂
直磁気記録方式に適用してきわめて効果大なるものであ
る。As is clear from the above description, according to the present invention, the S/N
Since a perpendicular magnetic recording medium with good properties can be obtained, it is extremely effective when applied to a perpendicular magnetic recording system.

【図面の簡単な説明】[Brief explanation of drawings]

第１図はこの発明の一実施例による媒体構造の要部断面
図、第２図は前回におけるＣｏ　−Ｃｒ膜の膜厚と粒径
との関係を示す図である。　□１：非磁性基板、２：高
透磁率磁性層、３：非磁性薄膜、４：下層Ｃｏ　−Ｃｒ
膜、５：Ｔｉ膜、６：上ｆｓ　１　図 第２図 Ｃｏ−Ｃｒ　ＦＩＶＥＯ−ｐｍ＞FIG. 1 is a sectional view of a main part of a medium structure according to an embodiment of the present invention, and FIG. 2 is a diagram showing the relationship between the thickness and grain size of the Co--Cr film in the previous test. □1: Nonmagnetic substrate, 2: High permeability magnetic layer, 3: Nonmagnetic thin film, 4: Lower layer Co-Cr
Film, 5: Ti film, 6: Upper fs 1 Fig. 2 Co-Cr FIVEO-pm>

Claims (1)

【特許請求の範囲】[Claims] 非磁性の基板上にＣｏ　−Ｃｒ合金の垂直磁化膜を形成
した垂直磁気記録媒体において、前記垂直磁化Ｃｏ　−
Ｃｒ膜を、Ｃｒ濃度の高い上層のＣｏ　−Ｃｒ膜とＣｒ
濃度の低い下層のＣｏ　−Ｃｒ膜との２層膜構造とした
ことを特徴とする垂直磁気記録媒体。In a perpendicular magnetic recording medium in which a perpendicularly magnetized film of Co-Cr alloy is formed on a non-magnetic substrate, the perpendicularly magnetized Co -
The Cr film is separated from the upper Co-Cr film with high Cr concentration.
A perpendicular magnetic recording medium characterized in that it has a two-layer structure with a Co--Cr film as a lower layer having a low concentration.