JPH08161723A - Magnetic recording medium - Google Patents
Magnetic recording mediumInfo
- Publication number
- JPH08161723A JPH08161723A JP30175794A JP30175794A JPH08161723A JP H08161723 A JPH08161723 A JP H08161723A JP 30175794 A JP30175794 A JP 30175794A JP 30175794 A JP30175794 A JP 30175794A JP H08161723 A JPH08161723 A JP H08161723A
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- Japan
- Prior art keywords
- magnetic layer
- thickness
- magnetic
- layer
- recording medium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、磁気記録媒体に関す
る。FIELD OF THE INVENTION The present invention relates to a magnetic recording medium.
【０００２】[0002]
【発明の背景】磁気テープや磁気ディスク等の磁気記録
媒体には、高密度記録化の要請から、磁性層としてバイ
ンダ樹脂を用いた塗布型のものではなく、バインダ樹脂
を用いない金属薄膜型のものがある。すなわち、無電解
メッキ等の湿式メッキ手段、真空蒸着、スパッタあるい
はイオンプレーティング等の乾式メッキ手段により磁性
層を構成した金属薄膜型の磁気記録媒体がある。この種
の磁気記録媒体は磁性体の充填密度が高いことから、高
密度記録に適したものである。BACKGROUND OF THE INVENTION Magnetic recording media such as magnetic tapes and magnetic disks are of a metal thin film type that does not use a binder resin, rather than a coating type that uses a binder resin as a magnetic layer, because of the demand for high density recording. There is something. That is, there is a metal thin film type magnetic recording medium in which the magnetic layer is constituted by a wet plating means such as electroless plating, or a dry plating means such as vacuum deposition, sputtering or ion plating. This type of magnetic recording medium is suitable for high-density recording because the packing density of the magnetic material is high.
【０００３】又、記録密度の向上を図る為に、基板材料
の見直しが進んでいる。その結果の一例として、カーボ
ン材料が提案（特公昭６３−４６００４号公報、神戸製
鋼技報、Ｖｏ１３９，Ｎｏ４，ｐｐ３５〜３８，１９８
９）されている。このカーボン材料は、軽量性、平滑
性、耐熱性、導電性などの優れた特長を有することか
ら、高密度記録に対応できる基板として注目されてい
る。Further, in order to improve the recording density, the substrate material is being reviewed. As an example of the result, a carbon material is proposed (Japanese Patent Publication No. 63-46004, Kobe Steel Technical Report, Vo139, No4, pp35-38, 198).
9) has been done. Since this carbon material has excellent features such as lightness, smoothness, heat resistance, and conductivity, it has attracted attention as a substrate that can be used for high-density recording.
【０００４】ところで、磁気記録媒体の再生に際して、
ノイズの小さいことが極めて好ましい。この為、低ノイ
ズ化への努力が払われている。しかしながら、低ノイズ
化を図ろうとすると、出力低下が起きていた。この問題
点を克服する為、磁性層を二層型磁性層とし、上層の磁
性層の保磁力を下層の磁性層の保磁力より高くし、か
つ、上層の磁性層の厚さと下層の磁性層の厚さを略同じ
にした磁気記録媒体が提案（特開平６−１０３５５１号
公報）されている。すなわち、下層の磁性層でノイズ特
性を改善し、上層の磁性層で出力特性を改善し、併せて
総合特性を良くしようとしたのである。By the way, when reproducing a magnetic recording medium,
Very low noise is highly preferred. Therefore, efforts are being made to reduce noise. However, when trying to reduce the noise, the output was reduced. In order to overcome this problem, the magnetic layer is a double-layer magnetic layer, the coercive force of the upper magnetic layer is made higher than that of the lower magnetic layer, and the thickness of the upper magnetic layer and the lower magnetic layer are Has been proposed (Japanese Patent Laid-Open No. 6-103551). In other words, the lower magnetic layer improved the noise characteristics, the upper magnetic layer improved the output characteristics, and also tried to improve the overall characteristics.
【０００５】しかし、この特開平６−１０３５５１号公
報で提案されている技術思想をカーボン製基板に応用し
ても、決して望むような結果が得られなかった。However, even if the technical idea proposed in Japanese Patent Laid-Open No. 6-103551 was applied to a carbon substrate, the desired result was never obtained.
【０００６】[0006]
【発明の開示】本発明の目的は、低ノイズ、高出力、高
密度記録が可能な磁気記録媒体を提供することである。
この本発明の目的は、カーボン製の基板上に磁性層が設
けられてなる磁気記録媒体であって、前記磁性層は二層
以上の磁性層が積層されたものであり、上層の磁性層の
保磁力は下層の磁性層の保磁力より高く、最下層の磁性
層の厚さ／全磁性層の厚さが０．４以下であることを特
徴とする磁気記録媒体によって達成される。DISCLOSURE OF THE INVENTION An object of the present invention is to provide a magnetic recording medium capable of low noise, high output and high density recording.
An object of the present invention is a magnetic recording medium in which a magnetic layer is provided on a carbon substrate, wherein the magnetic layer is a stack of two or more magnetic layers, and the magnetic layer of the upper layer is The coercive force is higher than the coercive force of the lower magnetic layer, and is achieved by the magnetic recording medium characterized in that the thickness of the lowermost magnetic layer / the thickness of the total magnetic layer is 0.4 or less.
【０００７】尚、本発明の磁気記録媒体における磁性層
の下には、例えばＣｒあるいはＣｒ合金系の下地層（非
磁性の下地層）が設けられていることが好ましい。尚、
下地層としてＣｒ系のもののみであっても良いが、下側
からＴｉあるいはＴｉ合金系の下地層が、その上にＣｒ
あるいはＣｒ合金系の下地層が設けられているタイプが
好ましい。Under the magnetic layer in the magnetic recording medium of the present invention, it is preferable that a Cr or Cr alloy based underlayer (nonmagnetic underlayer) is provided. still,
The underlying layer may be only a Cr-based one, but a Ti or Ti alloy-based underlayer from the bottom and Cr on top.
Alternatively, a type in which a Cr alloy-based underlayer is provided is preferable.
【０００８】又、本発明の磁気記録媒体における上層の
磁性層の保磁力は下層の磁性層の保磁力より高ければ良
いが、最上層の磁性層の保磁力Ｈchは最下層の磁性層の
保磁力Ｈclの約１．１倍以上が好ましい。より好ましく
は約１．３倍以上である。最下層の磁性層の厚さ／全磁
性層の厚さは０．４以下である。下限値の好ましい値は
０．００１である。より好ましくは０．０１である。更
に、好ましくは０．１である。上限値の好ましい値は
０．３５である。より好ましくは０．３である。In the magnetic recording medium of the present invention, the coercive force of the upper magnetic layer may be higher than that of the lower magnetic layer, but the coercive force Hch of the uppermost magnetic layer is the coercive force of the lowermost magnetic layer. It is preferable that the magnetic force is about 1.1 times or more of Hcl. It is more preferably about 1.3 times or more. The thickness of the lowermost magnetic layer / the thickness of all magnetic layers is 0.4 or less. The preferable lower limit is 0.001. It is more preferably 0.01. Further, it is preferably 0.1. The preferable upper limit value is 0.35. It is more preferably 0.3.
【０００９】本発明の磁気記録媒体は、基板がカーボン
製である。すなわち、磁気記録媒体の基板はカーボン、
特に好ましくはガラス状カーボンを用いて構成される。
カーボン材料は、密度が１．４〜２．０ｇ／ｃｍ3 、ビ
ッカース硬度が５５０〜７５０の特性を有しているもの
が好ましい。このカーボン材料には、 熱硬化性樹脂
を炭素化して得られるカーボン材料、 共重合や共縮
合などにより熱硬化するよう変性された樹脂を炭素化し
て得られるカーボン材料、 硬化あるいは炭素化の過
程で化学処理によって結晶化を著しく妨げることにより
得られるカーボン材料等がある。尚、カーボン製の基板
は、成膜に前もって、所定のテクスチャ処理が行われ
る。例えば、テープ研磨や電解研磨などの手段でテクス
チャ処理が行われる。これによって、Ｒａが約２５〜３
００Å、Ｒｐ／Ｒａ（Ｒａ＝中心線平均粗さ、Ｒｐ＝最
大中心線高さ）が約２．０〜６．０の特徴を有する基板
が得られる。The substrate of the magnetic recording medium of the present invention is made of carbon. That is, the magnetic recording medium substrate is carbon,
It is particularly preferable to use glassy carbon.
The carbon material preferably has a density of 1.4 to 2.0 g / cm 3 and a Vickers hardness of 550 to 750. This carbon material includes a carbon material obtained by carbonizing a thermosetting resin, a carbon material obtained by carbonizing a resin modified to be thermoset by copolymerization, cocondensation, etc., in the process of curing or carbonization. There are carbon materials and the like obtained by remarkably hindering crystallization by chemical treatment. It should be noted that the carbon substrate is subjected to a predetermined texture treatment prior to film formation. For example, texture processing is performed by means such as tape polishing or electrolytic polishing. As a result, Ra is about 25 to 3
A substrate having a characteristic of 00Å, Rp / Ra (Ra = centerline average roughness, Rp = maximum centerline height) of about 2.0 to 6.0 is obtained.
【００１０】カーボン製基板上に下地層が設けられる。
先ず、ＴｉあるいはＳｉ，Ｗ，Ａｌ，Ｃｒ，Ｍｏ，Ｚ
ｒ，Ｔａなどの元素を必須成分として含む（これらの副
成分元素の含有量は、最大でも５０ａｔ％）Ｔｉ合金系
の第１下地層が設けられる。すなわち、カーボン製基板
上に乾式メッキ手段で約１００〜２０００Å（好ましく
は約２００〜１０００Å）厚さのＴｉあるいはＴｉ合金
系の第１下地層が設けられる。この後、ＣｒあるいはＴ
ｉ，Ｖ，Ｍｏ，Ｃｏ，Ｎｉ，Ｆｅ，Ｗ，Ｔａ等の群の中
から選ばれる遷移金属元素を必須成分として含む（これ
らの副成分元素の含有量は、最大でも５０ａｔ％）Ｃｒ
合金系の第２下地層が設けられる。すなわち、第１下地
層上に乾式メッキ手段で約１００〜２０００Å（好まし
くは約２００〜１０００Å）厚さのＣｒあるいはＣｒ合
金系の第２下地層が設けられる。An underlayer is provided on a carbon substrate.
First, Ti or Si, W, Al, Cr, Mo, Z
A Ti alloy-based first underlayer containing elements such as r and Ta as essential components (the content of these sub-component elements is at most 50 at%) is provided. That is, a first underlayer of Ti or Ti alloy system having a thickness of about 100 to 2000Å (preferably about 200 to 1000Å) is provided on a carbon substrate by dry plating. After this, Cr or T
A transition metal element selected from the group of i, V, Mo, Co, Ni, Fe, W, Ta and the like is contained as an essential component (the content of these accessory component elements is at most 50 at%) Cr
An alloy-based second underlayer is provided. That is, a second underlayer of Cr or Cr alloy system having a thickness of about 100 to 2000Å (preferably about 200 to 1000Å) is provided on the first underlayer by dry plating.
【００１１】上記下地層上に磁性層が設けられる。先
ず、低保磁力の下層磁性層が設けられる。例えば、Ｃｏ
ＣｒＴａ，ＣｏＣｒＮｉ，ＣｏＮｉ，ＣｏＣｒ，ＣｏＣ
ｒＰｔ x Ｔａ（ｘ≦６ａｔ％），ＣｏＣｒＰｔx Ｂ（ｘ
≦６ａｔ％）等の比較的低保磁力、例えば約１０００〜
１８００Ｏｅ程度の保磁力を有する下層磁性層が乾式メ
ッキ手段で約１０〜５００Å（好ましくは約１０〜４０
０Å）厚さ設けられる。A magnetic layer is provided on the underlayer. Destination
First, a lower magnetic layer having a low coercive force is provided. For example, Co
CrTa, CoCrNi, CoNi, CoCr, CoC
rPt xTa (x ≦ 6 at%), CoCrPtxB (x
≤6 at%) and other relatively low coercive force, for example, about 1000-
The lower magnetic layer having a coercive force of about 1800 Oe is a dry type magnetic layer.
About 10 to 500 Å (preferably about 10 to 40)
0Å) Thickness is provided.
【００１２】この磁性層上に高保磁力の上層磁性層が設
けられる。例えば、ＣｏＣｒＰｔ，ＣｏＣｒＰｔy Ｘ
（但し、ＸはＢ，Ｔａ，Ｓｉ，Ｖ，Ｎｂ，Ｗ，Ｚｒある
いはＴｉであり、ｙ≧６ａｔ％）等の比較的高保磁力、
例えば約１５００〜３０００Ｏｅ程度の保磁力を有する
上層磁性層が乾式メッキ手段で約１０〜５００Å（好ま
しくは約１０〜４００Å）厚さ設けられる。尚、最上層
の磁性層の保磁力Ｈchは最下層の磁性層の保磁力Ｈclの
約１．１倍以上、好ましくは約１．３倍以上とすること
が望ましい。An upper magnetic layer of high coercive force is provided on this magnetic layer. For example, CoCrPt, CoCrPty y X
(However, X is B, Ta, Si, V, Nb, W, Zr, or Ti, and y ≧ 6 at%).
For example, an upper magnetic layer having a coercive force of about 1500 to 3000 Oe is provided by dry plating to a thickness of about 10 to 500Å (preferably about 10 to 400Å). The coercive force Hch of the uppermost magnetic layer is about 1.1 times or more, preferably about 1.3 times or more the coercive force Hcl of the lowermost magnetic layer.
【００１３】上記磁性層上に乾式メッキ手段によりカー
ボン等からなる保護層が設けられ、この保護層上に潤滑
剤層が設けられる。そして、上記のように構成させた磁
気記録媒体は、低ノイズで、高出力なものであり、高密
度記録が可能なものとなる。以下、具体的な実施例によ
り本発明を説明する。A protective layer made of carbon or the like is provided on the magnetic layer by dry plating, and a lubricant layer is provided on the protective layer. The magnetic recording medium configured as described above has low noise, high output, and enables high density recording. Hereinafter, the present invention will be described with reference to specific examples.
【００１４】[0014]
〔実施例１〕図１は、本発明になる磁気記録媒体の概略
図である。図中、１はガラス状カーボン製の基板であ
る。尚、基板１は、テクスチャ処理が行われ、表面のＲ
ａが約２５Å、Ｒｐが約２５０Å、板厚は０．６３５ｍ
ｍ、大きさは２．５インチ径である。尚、このガラス状
カーボンの物理的特性は、密度が１．８ｇ／ｃｍ3 、ビ
ッカース硬度が６５０である。[Embodiment 1] FIG. 1 is a schematic view of a magnetic recording medium according to the present invention. In the figure, 1 is a glassy carbon substrate. The substrate 1 is subjected to a texture process and the surface R
a is about 25Å, Rp is about 250Å, and the plate thickness is 0.635 m
m, size is 2.5 inch diameter. The glassy carbon has physical properties of a density of 1.8 g / cm 3 and a Vickers hardness of 650.
【００１５】２は、１０００Å厚さのＴｉ下地層であ
る。すなわち、ガラス状カーボン製基板１に対して、Ａ
ｒガス圧２ｍＴｏｒｒ、基板温度２６０℃の条件下でＤ
Ｃマグネトロンスパッタ装置を用いて、金属Ｔｉを堆積
させたものである。３は、４５０Å厚さのＣｒ下地層で
ある。すなわち、Ｔｉ下地層２上に、Ａｒガス圧２ｍＴ
ｏｒｒ、基板温度２６０℃の条件下でＤＣマグネトロン
スパッタ装置を用いて、金属Ｃｒを堆積させたものであ
る。Reference numeral 2 is a Ti underlayer having a thickness of 1000Å. That is, for the glassy carbon substrate 1, A
Under the conditions of r gas pressure of 2 mTorr and substrate temperature of 260 ° C, D
Metallic Ti is deposited using a C magnetron sputtering apparatus. 3 is a 450 Å thick Cr underlayer. That is, on the Ti underlayer 2, an Ar gas pressure of 2 mT
Metal Cr was deposited using a DC magnetron sputtering apparatus under the conditions of orr and substrate temperature of 260 ° C.
【００１６】４は、５００Å以下の厚さのＣｏＣｒＴａ
磁性層である。すなわち、Ｃｒ下地層３上に、Ａｒガス
圧２ｍＴｏｒｒ、基板温度２６０℃の条件下でＤＣマグ
ネトロンスパッタ装置を用いて、磁性金属ＣｏＣｒＴａ
（８６：１２：２）を堆積させたものである。尚、この
金属磁性膜単体の保磁力Ｈc1は１５１０Ｏｅであった。4 is CoCrTa having a thickness of 500 Å or less
It is a magnetic layer. That is, the magnetic metal CoCrTa was deposited on the Cr underlayer 3 using a DC magnetron sputtering apparatus under the conditions of Ar gas pressure of 2 mTorr and substrate temperature of 260 ° C.
(86: 12: 2) is deposited. The coercive force Hc1 of this metal magnetic film alone was 1510 Oe.
【００１７】５は、５００Å以下の厚さのＣｏＣｒＰｔ
磁性層である。すなわち、ＣｏＣｒＴａ磁性層４上に、
Ａｒガス圧２ｍＴｏｒｒ、基板温度２６０℃の条件下で
ＤＣマグネトロンスパッタ装置を用いて、磁性金属Ｃｏ
ＣｒＰｔ（７８：１０：１２）を堆積させたものであ
る。尚、この金属磁性膜単体の保磁力Ｈc2は１９８０Ｏ
ｅであった。5 is CoCrPt with a thickness of 500 Å or less
It is a magnetic layer. That is, on the CoCrTa magnetic layer 4,
Using a DC magnetron sputtering device under the conditions of Ar gas pressure of 2 mTorr and substrate temperature of 260 ° C., magnetic metal Co
CrPt (78:10:12) is deposited. The coercive force Hc2 of this metallic magnetic film alone is 1980O.
It was e.
【００１８】６はカーボン保護層、７はパーフルオロエ
ーテル系の潤滑剤層である。この磁気ディスクについ
て、ＣｏＣｒＴａ磁性層の厚さ／（ＣｏＣｒＴａ磁性層
の厚さ＋ＣｏＣｒＰｔ磁性層の厚さ）と保磁力Ｈｃとの
関係を調べた処、図２に示される結果が得られた。これ
によれば、ＣｏＣｒＴａ磁性層の厚さ／（ＣｏＣｒＴａ
磁性層の厚さ＋ＣｏＣｒＰｔ磁性層の厚さ）が０．４以
下の場合には、保磁力Ｈｃが、ＣｏＣｒＴａ磁性層のみ
の場合の保磁力ＨclとＣｏＣｒＰｔ磁性層のみの場合の
保磁力Ｈchの単純平均値よりも大きいことが判る。特
に、ＣｏＣｒＴａ磁性層の厚さ／（ＣｏＣｒＴａ磁性層
の厚さ＋ＣｏＣｒＰｔ磁性層の厚さ）が０．３以下の場
合には、保磁力Ｈｃが、ＣｏＣｒＰｔ磁性層のみの場合
の保磁力Ｈchよりも大きいことが判る。そして、０．５
を越えると、ＣｏＣｒＴａ磁性層のみの場合の保磁力Ｈ
clとＣｏＣｒＰｔ磁性層のみの場合の保磁力Ｈchの単純
平均値にほぼ等しい値になっている。すなわち、基板材
料がガラスである特開平６−１０３５５１号とは全く異
なる挙動を示している。Reference numeral 6 is a carbon protective layer, and 7 is a perfluoroether type lubricant layer. When the relationship between the thickness of the CoCrTa magnetic layer / (the thickness of the CoCrTa magnetic layer + the thickness of the CoCrPt magnetic layer) and the coercive force Hc of this magnetic disk was investigated, the results shown in FIG. 2 were obtained. According to this, the thickness of the CoCrTa magnetic layer / (CoCrTa
When the magnetic layer thickness + the thickness of the CoCrPt magnetic layer) is 0.4 or less, the coercive force Hc is simply the coercive force Hcl in the case of only the CoCrTa magnetic layer and the coercive force Hch in the case of only the CoCrPt magnetic layer. It can be seen that it is larger than the average value. In particular, when the thickness of the CoCrTa magnetic layer / (the thickness of the CoCrTa magnetic layer + the thickness of the CoCrPt magnetic layer) is 0.3 or less, the coercive force Hc is larger than the coercive force Hch in the case of only the CoCrPt magnetic layer. It turns out to be big. And 0.5
Beyond, the coercive force H in the case of CoCrTa magnetic layer only
The value is almost equal to the simple average value of the coercive force Hch in the case of only cl and the CoCrPt magnetic layer. That is, the behavior is completely different from that of JP-A-6-103551 in which the substrate material is glass.
【００１９】又、ＣｏＣｒＴａ磁性層の厚さ／（ＣｏＣ
ｒＴａ磁性層＋ＣｏＣｒＰｔ磁性層）とＳ／Ｎ（ＣｏＣ
ｒＰｔ磁性層のみの場合のＳ／Ｎを基準とした場合の相
対Ｓ／Ｎ）との関係を調べた処、図３に示される結果が
得られた。これによれば、ＣｏＣｒＴａ磁性層の厚さ／
（ＣｏＣｒＴａ磁性層の厚さ＋ＣｏＣｒＰｔ磁性層の厚
さ）が大きくなるにつれて、Ｓ／Ｎの向上していること
が判る。Further, the thickness of the CoCrTa magnetic layer / (CoC
rTa magnetic layer + CoCrPt magnetic layer) and S / N (CoC
When the relationship with the relative S / N based on the S / N in the case of only the rPt magnetic layer was examined, the results shown in FIG. 3 were obtained. According to this, the thickness of the CoCrTa magnetic layer /
It can be seen that the S / N is improved as (CoCrTa magnetic layer thickness + CoCrPt magnetic layer thickness) increases.
【００２０】従って、図２及び図３から、ＣｏＣｒＴａ
磁性層の厚さ／（ＣｏＣｒＴａ磁性層の厚さ＋ＣｏＣｒ
Ｐｔ磁性層の厚さ）が０．４以下、好ましくは０．３５
以下、より好ましくは０．３以下の場合には、高保磁
力、高Ｓ／Ｎの磁気記録媒体か得られることが判る。
尚、この値は零に限りなく近い場合でもそれなりの効果
がある。但し、総合的に判断したならば、０．００１以
上、より好ましくは０．０１以上、更に好ましくは０．
１以上が望ましい。Therefore, from FIG. 2 and FIG. 3, CoCrTa
Magnetic layer thickness / (CoCrTa magnetic layer thickness + CoCr
Pt magnetic layer thickness) is 0.4 or less, preferably 0.35
It is understood that a magnetic recording medium having a high coercive force and a high S / N can be obtained when the ratio is less than 0.3, more preferably less than 0.3.
Even if this value is as close to zero as possible, there is some effect. However, when comprehensively judged, 0.001 or more, more preferably 0.01 or more, still more preferably 0.
1 or more is desirable.
【００２１】〔実施例２〕実施例１において、ＣｏＣｒ
Ｔａの代わりにＣｏＣｒＰｔＴａ（８０：１０：６：
４）を用いた以外は実施例１に準じて磁気ディスクを得
た。そして、ＣｏＣｒＰｔＴａ磁性層の厚さ／（ＣｏＣ
ｒＰｔＴａ磁性層の厚さ＋ＣｏＣｒＰｔ磁性層の厚さ）
と保磁力Ｈｃとの関係を調べた処、図４に示される結果
が得られた。[Example 2] In Example 1, CoCr
CoCrPtTa (80: 10: 6: instead of Ta)
A magnetic disk was obtained in the same manner as in Example 1 except that 4) was used. Then, the thickness of the CoCrPtTa magnetic layer / (CoC
(rPtTa magnetic layer thickness + CoCrPt magnetic layer thickness)
The result shown in FIG. 4 was obtained by examining the relationship between the coercive force Hc and the coercive force Hc.
【００２２】これによれば、ＣｏＣｒＰｔＴａ磁性層の
厚さ／（ＣｏＣｒＰｔＴａ磁性層の厚さ＋ＣｏＣｒＰｔ
磁性層の厚さ）が０．４以下の場合には、保磁力Ｈｃ
が、ＣｏＣｒＰｔＴａ磁性層のみの場合の保磁力とＣｏ
ＣｒＰｔ磁性層のみの場合の保磁力の単純平均値よりも
大きいことが判る。特に、ＣｏＣｒＰｔＴａ磁性層の厚
さ／（ＣｏＣｒＰｔＴａ磁性層の厚さ＋ＣｏＣｒＰｔ磁
性層の厚さ）が０．３以下の場合には、保磁力Ｈｃが、
ＣｏＣｒＰｔ磁性層のみの場合の保磁力よりも大きいこ
とが判る。そして、０．５を越えると、ＣｏＣｒＰｔＴ
ａ磁性層のみの場合の保磁力とＣｏＣｒＰｔ磁性層のみ
の場合の保磁力の単純平均値にほぼ等しい値になってい
る。すなわち、基板材料がガラスである特開平６−１０
３５５１号とは全く異なる挙動を示している。According to this, the thickness of the CoCrPtTa magnetic layer / (the thickness of the CoCrPtTa magnetic layer + CoCrPt)
When the thickness of the magnetic layer is less than 0.4, the coercive force Hc
Is the coercive force and Co of the CoCrPtTa magnetic layer only.
It can be seen that it is larger than the simple average value of the coercive force in the case of only the CrPt magnetic layer. In particular, when the thickness of the CoCrPtTa magnetic layer / (the thickness of the CoCrPtTa magnetic layer + the thickness of the CoCrPt magnetic layer) is 0.3 or less, the coercive force Hc is
It can be seen that it is larger than the coercive force of the CoCrPt magnetic layer alone. And, when it exceeds 0.5, CoCrPtT
The value is almost equal to the simple average value of the coercive force in the case of only the magnetic layer a and the coercive force in the case of only the CoCrPt magnetic layer. That is, the substrate material is glass.
It shows a completely different behavior from No. 3551.
【００２３】又、ＣｏＣｒＰｔＴａ磁性層の厚さ／（Ｃ
ｏＣｒＰｔＴａ磁性層の厚さ＋ＣｏＣｒＰｔ磁性層の厚
さ）とＳ／Ｎ（ＣｏＣｒＰｔ磁性層のみの場合のＳ／Ｎ
を基準とした場合の相対Ｓ／Ｎ）との関係を調べた処、
図３の場合と同様な傾向が認められた。すなわち、Ｃｏ
ＣｒＰｔＴａ磁性層の厚さ／（ＣｏＣｒＰｔＴａ磁性層
の厚さ＋ＣｏＣｒＰｔ磁性層の厚さ）が大きくなるにつ
れて、Ｓ／Ｎが向上していた。The thickness of the CoCrPtTa magnetic layer / (C
oCrPtTa magnetic layer thickness + CoCrPt magnetic layer thickness) and S / N (S / N in case of only CoCrPt magnetic layer)
As a result of investigating the relation with relative S / N) with reference to
The same tendency as in the case of FIG. 3 was recognized. That is, Co
The S / N ratio was improved as the thickness of the CrPtTa magnetic layer / (the thickness of the CoCrPtTa magnetic layer + the thickness of the CoCrPt magnetic layer) increased.
【００２４】従って、ＣｏＣｒＰｔＴａ磁性層の厚さ／
（ＣｏＣｒＰｔＴａ磁性層の厚さ＋ＣｏＣｒＰｔ磁性層
の厚さ）が０．４以下、好ましくは０．３５以下、より
好ましくは０．３以下の場合には、高保磁力、高Ｓ／Ｎ
の磁気記録媒体か得られることが判る。尚、この値は零
に限りなく近い場合でもそれなりの効果はある。但し、
総合的に判断したならば、０．００１以上、より好まし
くは０．０１以上、更に好ましくは０．１以上が望まし
い。Therefore, the thickness of the CoCrPtTa magnetic layer /
When (CoCrPtTa magnetic layer thickness + CoCrPt magnetic layer thickness) is 0.4 or less, preferably 0.35 or less, and more preferably 0.3 or less, a high coercive force and a high S / N ratio are obtained.
It can be seen that this magnetic recording medium can be obtained. Even if this value is as close to zero as possible, there is some effect. However,
When comprehensively judged, 0.001 or more, more preferably 0.01 or more, and further preferably 0.1 or more is desirable.
【００２５】[0025]
【効果】本発明によれば、低ノイズ、高出力、高密度記
録が可能な磁気記録媒体が得られる。According to the present invention, a magnetic recording medium capable of low noise, high output and high density recording can be obtained.
【図１】磁気記録媒体の概略図FIG. 1 is a schematic diagram of a magnetic recording medium.
【図２】Ｈｃを示すグラフFIG. 2 is a graph showing Hc
【図３】Ｓ／Ｎを示すグラフFIG. 3 is a graph showing S / N
【図４】Ｈｃを示すグラフFIG. 4 is a graph showing Hc
１ ガラス状カーボン製基板 ２ Ｔｉ下地層 ３ Ｃｒ下地層 ４ ＣｏＣｒＴａ磁性層 ５ ＣｏＣｒＰｔ磁性層 ６ カーボン保護層 ７ パーフルオロエーテル系潤滑剤層 1 Glassy Carbon Substrate 2 Ti Underlayer 3 Cr Underlayer 4 CoCrTa Magnetic Layer 5 CoCrPt Magnetic Layer 6 Carbon Protective Layer 7 Perfluoroether Lubricant Layer
Claims (4)
てなる磁気記録媒体であって、 前記磁性層は二層以上の磁性層が積層されたものであ
り、 上層の磁性層の保磁力は下層の磁性層の保磁力より高
く、 最下層の磁性層の厚さ／全磁性層の厚さが０．４以下で
あることを特徴とする磁気記録媒体。1. A magnetic recording medium in which a magnetic layer is provided on a carbon substrate, wherein the magnetic layer is a stack of two or more magnetic layers, and the coercive force of the upper magnetic layer. Is higher than the coercive force of the lower magnetic layer, and the thickness of the lowermost magnetic layer / the thickness of all magnetic layers is 0.4 or less.
ことを特徴とする請求項１の磁気記録媒体。2. The magnetic recording medium according to claim 1, wherein an underlayer is provided below the magnetic layer.
Ｔｉ合金系の下地層が、その上にＣｒあるいはＣｒ合金
系の下地層が設けられていることを特徴とする請求項１
の磁気記録媒体。3. A Ti or Ti alloy-based underlayer is provided from the lower side below the magnetic layer, and a Cr or Cr alloy-based underlayer is provided thereon.
Magnetic recording medium.
を特徴とする請求項１〜請求項３いずれかの磁気記録媒
体。4. The magnetic recording medium according to claim 1, wherein the magnetic layer is a metal thin film type magnetic layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30175794A JPH08161723A (en) | 1994-12-06 | 1994-12-06 | Magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30175794A JPH08161723A (en) | 1994-12-06 | 1994-12-06 | Magnetic recording medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08161723A true JPH08161723A (en) | 1996-06-21 |
Family
ID=17900806
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30175794A Pending JPH08161723A (en) | 1994-12-06 | 1994-12-06 | Magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08161723A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20040033492A (en) * | 2002-10-14 | 2004-04-28 | 한국과학기술원 | High density magnetic recording media having uniform local coercivity distribution and grain size distribution and manufacturing method thereof |
-
1994
- 1994-12-06 JP JP30175794A patent/JPH08161723A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20040033492A (en) * | 2002-10-14 | 2004-04-28 | 한국과학기술원 | High density magnetic recording media having uniform local coercivity distribution and grain size distribution and manufacturing method thereof |
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