JPS62120621A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a reproduction signal of S/N substantial in a wide frequency range by specifying the ratio between the 1st layer and the 2nd layer of the sizes of the pulverized particles constituting a thin film. CONSTITUTION:This magnetic recording medium is formed by disposing a magnetic recording layer having two-layered structure on a high-polymer film and constituting the thin films in such a manner that the pulverized particle size of the 2nd layer is in a 1.3-2 range if the size of the pulverized particles constituting the 1st layer of the thin films is assumed to be 1. More specifically, the size represented by the value D1 in the figure has the high correlation with noise and therefore the size of the pulverized particle 6 of the 1st layer is defined by D1 even if the pulverized particles have respectively different particle shapes including elliptical and circular columnar shapes. D2 shown in the figure is designated as the size of the pulverized particles 7 for the 2nd layer. The superiority of S/N with the recording layer of which the 2nd layer has the particle size ranging 1.3-2 times the particle size of the 1st layer is verified in the 70-300Angstrom range of the particle size of the 1st layer. A 1.5-1.7 times range is satisfactory when the particle size of the 1st layer increases from 300Angstrom -500Angstrom .

Description

【発明の詳細な説明】 産業上の利用分野 本発明は高密度磁気記録に適した磁気テープ。[Detailed description of the invention] Industrial applications The present invention is a magnetic tape suitable for high-density magnetic recording.

磁気ディスク等の磁気記録媒体に関する。It relates to magnetic recording media such as magnetic disks.

従来の技術 近年、磁気記録の高密度化をめざして、強磁性金属薄膜
を磁気記録層とする磁気記録媒体の研究が盛んに行われ
ている。かかる磁気記録媒体は、一般にポリエチレンテ
レフタレート等の非磁性基板上に、　（ｊｏ等の強磁性
金属薄膜（膜厚；数１００Ａ〜１１１ｍ）を直接形成さ
せたものである（以下これをＭＥテープと呼ぶ）。BACKGROUND OF THE INVENTION In recent years, with the aim of increasing the density of magnetic recording, research has been actively conducted on magnetic recording media in which a ferromagnetic metal thin film is used as a magnetic recording layer. Such magnetic recording media are generally those in which a ferromagnetic metal thin film (thickness: several 100 Å to 111 m) such as (JO) is directly formed on a non-magnetic substrate such as polyethylene terephthalate (hereinafter referred to as ME tape). ).

ＭＥテープは、磁気記録層を薄くしても十分大きな磁束
を発生せしめることが可能であり、斜め蒸着や、蒸着中
に酸素を導入して、保磁力を大きくすることで、短波長
記録再生出力が太きく、今後の磁気記録媒体の中にあっ
て重要な位＃を占めるものである〔例えば、外国論文誌
、アイ・イー・イー・イー磁気学会報（ＩＥＩＣＥ　Ｔ
ｒａｎｓａｃｔｉｏｎ　ｏｎｕａｇｎｅｔｉｃｓ　）、
Ｖｏｌ　、ＭＡＧ−２１、Ｎｏ−３，ＰＰ　、１２１７
〜１２２０（１９８５）参照〕０ 周知のように、磁気記録媒体の改良は出力だけでは不十
分で雑音の改良が不可欠である。ME tape can generate a sufficiently large magnetic flux even if the magnetic recording layer is made thin, and by increasing the coercive force by diagonal deposition or by introducing oxygen during deposition, short wavelength recording and reproduction output can be achieved. It has a large diameter and will occupy an important position in future magnetic recording media [for example, foreign journals, IEICE T
transaction onuagnetics),
Vol, MAG-21, No-3, PP, 1217
1220 (1985)] 0 As is well known, in improving magnetic recording media, it is not enough to improve the output alone; it is essential to improve the noise.

特に変調ノイズを小なくするには表面性を良くする必要
があり、走行性能を実用範囲にとどめておくために、表
面形状に関して工夫がされている〔例えば、特開昭５９
−８４９２８号、特開昭５９−１２１６３１号公報参照
〕。In particular, in order to reduce modulation noise, it is necessary to improve the surface properties, and in order to keep running performance within a practical range, improvements have been made to the surface shape [for example, JP-A-59
-84928, JP-A-59-121631].

発参照群決しようとする問題点 しかしながら、上記したような構成では、画像記録のよ
うに広帯域での信号の記録再生を十分犬きい信号対雑音
（Ｓ／Ｎと以下記す）比を得るのに、磁気記録層自身か
ら発生する雑音が問題となる０ 特に光磁気記録に近い高密度記録で画像記録再生を目指
すには、磁化容易軸の方向の如何を問わず磁気記録層の
雑音を改良する必要がある。Problems with trying to determine the source reference group However, with the above configuration, it is difficult to obtain a signal-to-noise (hereinafter referred to as S/N) ratio that is sufficiently high for recording and reproducing signals in a wide band such as image recording. , the noise generated from the magnetic recording layer itself becomes a problem. In particular, in order to achieve image recording and reproduction with high-density recording close to magneto-optical recording, it is necessary to improve the noise of the magnetic recording layer regardless of the direction of the easy axis of magnetization. There is a need.

本発明は上記事情に鑑みなされたもので、磁気記録層自
身の雑音成分を小さくして、広帯域で十分なＳ／Ｎの再
生信号を得られるようにした磁気記録媒体を提供するも
のである。The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a magnetic recording medium in which the noise component of the magnetic recording layer itself is reduced and a reproduced signal with a sufficient S/N ratio can be obtained over a wide band.

問題点を解決するための手段 上記した問題点を解決するため、本発明の磁気記録媒体
は、高分子フィルム上に２層構造の磁気記録層を配し、
薄膜を構成する微粒子サイズが第１層を１とすると、第
２層が１．３から２の範囲にあるよう構成したものであ
る。Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention has a two-layered magnetic recording layer disposed on a polymer film,
If the size of the particles constituting the thin film is 1 in the first layer, the size of the particles in the second layer is in the range of 1.3 to 2.

作用 上記した構成により本発明の磁気記録媒体は、リング型
磁気ヘッドの形成する磁界により記録される時に、短波
長時は、ヘッドより遠い側は、磁界が弱いため、磁気的
により均一でないと雑音が増えるが、第１磨機粒子が第
２層より小さいため硼気的均−性が良く、第２層の磁気
抵抗は第１層より小さいので、磁束の伝達能率は良く、
従って記録、再生に於て、第１層のＳ／Ｎ寄与分は大幅
に向上する。又、第２層はヘッドに近いので、十分磁界
が強いので、不均一性が少々あっても完全に磁場反転で
き、不均一性に基ずく雑音レベルは実効的に小さくでき
る。Effects Due to the above-described configuration, the magnetic recording medium of the present invention has the advantage that when recording is performed using the magnetic field formed by the ring-shaped magnetic head, when the wavelength is short, the magnetic field is weaker on the side farther from the head, so if it is not magnetically more uniform, noise will occur. However, since the first polishing particles are smaller than the second layer, the magnetic uniformity is good, and the magnetic resistance of the second layer is smaller than the first layer, so the magnetic flux transmission efficiency is good.
Therefore, in recording and reproduction, the S/N contribution of the first layer is greatly improved. Furthermore, since the second layer is close to the head, the magnetic field is sufficiently strong, so even if there is some non-uniformity, the magnetic field can be completely reversed, and the noise level due to non-uniformity can be effectively reduced.

又、全体として、１層の微粒子からなる磁気記録層に比
べて、ヘッドからみて、同一膜厚での磁気的粒子の大き
さが小さくなるので、その効果によるＳ／Ｎ改良も見込
める。以上のべたような作用により本発明の磁気記録媒
体は、良好なＳ／Ｎを与えることができるのである。In addition, as a whole, the size of the magnetic particles at the same film thickness is smaller when viewed from the head than in a single layer of magnetic recording layer made up of fine particles, so an S/N improvement can be expected due to this effect. Due to the above-described effects, the magnetic recording medium of the present invention can provide a good S/N ratio.

実施例 以下、図面を参照しながら本発明の実施例の磁気記録媒
体について説明する。EXAMPLES Below, magnetic recording media according to examples of the present invention will be described with reference to the drawings.

第１図は本発明の磁気記録媒体の拡大断面図である。FIG. 1 is an enlarged sectional view of the magnetic recording medium of the present invention.

第１図に於て、１は厚み１ｏμｍのポリエチレンテレフ
タレートフィルムで、２は第１４膜層。In FIG. 1, 1 is a polyethylene terephthalate film with a thickness of 1 μm, and 2 is the 14th film layer.

３は第２薄膜層で、いずれも磁化容易軸方向がポリエチ
レンテレフタレートフィルム面にほぼ垂直方向にあるＧ
ｏ−ｃｒ　（Ｏｒ　２０．３　ｗｔ％〕から成り、第１
薄膜層の粒子サイズ（第２図でのＤｌに相当するものを
指す）は平均１６０人、第２薄膜層の粒子サイズ（同Ｄ
２に相当するものを指す）は２０ＯＡ’ｉテ一プ人、２
８ＯＡ’ｉチー７’Ｂ。3 is the second thin film layer, in which the axis of easy magnetization is almost perpendicular to the surface of the polyethylene terephthalate film.
o-cr (Or 20.3 wt%), the first
The particle size of the thin film layer (corresponding to Dl in Figure 2) is 160 people on average, and the particle size of the second thin film layer (corresponding to Dl in Figure 2) is 160 people.
2) refers to the equivalent of 20OA'i 1 person, 2
8OA'i Chi7'B.

３２０ＡをテープＣとした。320A was used as tape C.

尚夫々の膜厚は１０００八で同一とした。Ｇｏ−Ｃｒの
第１層、第２層は、高周波スパッタ法で形成し、粒子サ
イズの調整は、ポリエチレンテレフタレートフィルムの
支持体を兼ねる円筒状キャン（直径６ｏα）の表面温度
を変化させて行った。The thickness of each film was the same at 1,000 mm. The first and second layers of Go-Cr were formed by high-frequency sputtering, and the particle size was adjusted by changing the surface temperature of a cylindrical can (diameter 6oα) that also served as a support for the polyethylene terephthalate film. .

ちなみに粒子サイズ、１６０人、２ｏ〇八、２８゜Ａ、
３２０八を得るに用いた表面温度は夫々６７’Ｃ、８５
°Ｃ１９９°Ｃ，１１６°Ｃであった。By the way, the particle size is 160 people, 2o8, 28°A,
The surface temperatures used to obtain 3208 were 67'C and 85'C, respectively.
The temperatures were 199°C and 116°C.

４は厚み約３０へのパーフロロオクタン酸の蒸着膜で、
６はカーボン３ｏ重量部、エポキシ樹脂１００重量部か
ら成る厚み０．６５μｍのバックコート層で、テープの
走行性を改良するために設けられた塗布層である。4 is a vapor-deposited film of perfluorooctanoic acid to a thickness of about 30 mm,
Reference numeral 6 denotes a 0.65 μm thick back coat layer made of 30 parts by weight of carbon and 100 parts by weight of epoxy resin, and is a coating layer provided to improve the running properties of the tape.

それぞれのテープｋ、４０”の直径の回転シリンダに、
リング型のアモルファス合金ヘッド（ギャップ長０．１
９μｍ）を搭さいして、記録波長０．２８μｍ、）ラッ
ク幅７μｍ＝６記録した時のＳ／Ｎを比較した。尚、０
．２８μｍは６　ＭＨ２に相当し、ノイズは０〜１１Ｍ
Ｈ２の範囲の広帯域の２乗平均である。Each tape k, in a rotating cylinder of 40” diameter,
Ring-shaped amorphous alloy head (gap length 0.1
The S/N was compared when 6 recordings were made with a recording wavelength of 0.28 μm and a rack width of 7 μm. Furthermore, 0
．． 28μm is equivalent to 6MH2, noise is 0~11M
It is the broadband mean square of the H2 range.

尚比較テープとして、厚み０．２μｍ、粒子サイズ３０
０への従来知らｎる単一膜のＧｏ−Ｏｒ（Ｏｒ２０．３
ｗｔ％）を準備し、このＳ／Ｎ′１ｔＯ（ｄＪとしてテ
ープＡ、Ｂ、ＣについてＳ／Ｎ’ｉ測定した結果、夫々
３．３　、３．６　、３．１（ｄＢ）とＳ／Ｎが大きか
った。As a comparative tape, the thickness was 0.2 μm and the particle size was 30.
0 to the conventionally known single film Go-Or (Or20.3
wt%) was prepared, and the S/N'i was measured as S/N'1tO (dJ) for tapes A, B, and C. The S/N'i was 3.3, 3.6, and 3.1 (dB), respectively. N was large.

第２図は粒子サイズの説明図で、６は第１層の微粒子で
サイズＨ１Ｄ１の値で代表されるものがノイズと強い相
関を持っているので、楕円状２円柱状とそれぞれ異なる
粒子形状を呈していてもり。Figure 2 is an explanatory diagram of particle size. 6 is a fine particle in the first layer, and the size represented by the value H1D1 has a strong correlation with noise, so different particle shapes are used, such as elliptical, 2 cylindrical, and cylindrical. It's a bit of a bit of a bit of a bit of a bit of a bit of a bit of a bit of a bit of a bit.

で定義すればよいと考えられる。同じく７は第２層の微
粒子で、これについてもｉ　Ｄ２に粒子サイズと呼ぶも
のとする。It may be appropriate to define it as Similarly, 7 is a second layer of fine particles, which is also referred to as iD2 and particle size.

斜め蒸着法により得られる微粒子は、変形された微粒子
形状を呈することがあるが、この場合は最大となるＤ＋
ｙＤｚｋとればよい。Fine particles obtained by oblique vapor deposition may have a deformed particle shape, but in this case, the maximum D+
Just take yDzk.

尚、第１層の粒子サイズに対して、第２層が１．３倍か
ら２倍の範囲にあるものがＳ／Ｎが優れていることは、
第１層の粒子サイズが７０八から３ｏＯへの範囲で確か
められたものであるが、３００八から５００人に第１層
の粒子サイズが大きくなった時は１．５倍から１．７倍
の範囲が良好である。０．３μｍ近辺の記録波長の実用
化を前提にした時には、粒子サイズは記録波長の殉以下
でないと、ノイズが犬きくなる場合があるので、３００
八以下を前提としても差し支えないと考えている。Furthermore, the fact that the second layer has an excellent S/N ratio of 1.3 to 2 times the particle size of the first layer is as follows.
It was confirmed that the particle size of the first layer ranged from 708 to 3oO, but when the particle size of the first layer increased from 3008 to 500, it was 1.5 times to 1.7 times. The range is good. When assuming the practical use of recording wavelengths around 0.3 μm, the noise may become too loud unless the particle size is smaller than the recording wavelength.
I think it is safe to assume that the number is 8 or less.

本発明の実施例は、テープ状で説明したが、ディスク状
であっても良いのは勿論である。Although the embodiments of the present invention have been described in the form of a tape, it goes without saying that it may be in the form of a disk.

高分子フィルムはポリエチレンテレフタレートフィルム
としたが、ポリエチレンナフタレート。The polymer film used was polyethylene terephthalate film, but polyethylene naphthalate was used instead.

ポリアミド、ポリイミド等としても良い。It may also be made of polyamide, polyimide, etc.

磁気記録層としてＧｏ−Ｃｒ垂直磁化膜を用いたが、他
にＧｏ−Ｔｉ、Ｇｏ−Ｗ、Ｇｏ−Ｍｏ、Ｇｏ−０，Ｇｏ
　−０ｒ−Ｎｂ等の垂直磁化膜、Ｇｏ−Ｏｒ　、　Ｇｏ
−Ｂｉ　、　Ｇ。A Go-Cr perpendicular magnetization film was used as the magnetic recording layer, but other materials include Go-Ti, Go-W, Go-Mo, Go-0, and Go.
Perpendicular magnetization film such as -0r-Nb, Go-Or, Go
-Bi, G.

−人１　、　Ｇｏ−Ａｇ　、Ｇｏ−Ｆｅ　、Ｇｏ　−Ｎ
ｉ　、　Ｇｏ−Ｎｉ　−０。-Person 1, Go-Ag, Go-Fe, Go-N
i, Go-Ni-0.

Ｇｏ−Ｎｉ−Ｐｔ等の斜め蒸着膜等としても良い。An obliquely deposited film such as Go-Ni-Pt may also be used.

発明の効果 以上のように本発明によれば、高密度記録再生ヲリング
型磁気へクドにより行った時、優れたＳ／Ｎを得ること
ができるといったすぐれた効果が得られる。Effects of the Invention As described above, according to the present invention, excellent effects such as an excellent S/N ratio can be obtained when high-density recording/reproduction is performed using a Woring-type magnetic heculator.

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

第１図は本発明の実施例の磁気記録媒体の拡大断面図、
第２図は本発明の粒子サイズの説明のための模式図であ
る。 １・・・・・・ポリエチレンテレフタレートフィルム、
２・・・・・・第１層、３・・・・・・第２層。FIG. 1 is an enlarged cross-sectional view of a magnetic recording medium according to an embodiment of the present invention;
FIG. 2 is a schematic diagram for explaining the particle size of the present invention. 1...Polyethylene terephthalate film,
2...First layer, 3...Second layer.

Claims (1)

【特許請求の範囲】[Claims] 高分子フィルム上に２層構造を有する強磁性金属薄膜を
配した磁気記録層の、薄膜を構成する微粒子サイズが第
１層を１とすると、第２層が１．３倍から２倍の範囲に
あることを特徴とする磁気記録媒体。In a magnetic recording layer in which a ferromagnetic metal thin film with a two-layer structure is arranged on a polymer film, the particle size of the thin film is in the range of 1.3 to 2 times that of the second layer when the first layer is 1. A magnetic recording medium characterized by: