JPS6166219A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium having good S/N by using a ring type magnetic head in narrow-track recording and reproduction by maintaining the ratio between the coercive forces of the thin ferromagnetic film in the longitudinal direction thereof and in the direction orthogonal therewith within a specific ratio. CONSTITUTION:Fine particles such as SiO2 particles are fixed at about average 6 pieces/mu<2> by a polyester resin, etc. on a substrate 1 consisting of a polyester film, etc. and thereafter a magnetic recording film 2 is formed by electron beam vapor deposition, etc. of a ferromagnetic metal such as Co, Co-Ni or Co-Ni-P thereon. The film 2 is so formed that the ratio between the coercive force Hc1 in the longitudinal direction of the film 2 and the coercive force Hc2 in the direction orthogonal with the longitudinal direction satisfies the relation 1.8<=Hc1/Hc2<=3.0 by adjusting the focusing state, scanning waveform and min. incident angle of the beam in the stage of forming the film 2. The magnetic recording medium which has high S/N and is suitable for high-density recording is thus obtd. by using the ring type magnetic head. A protective layer 3 and back coat layer 4 may be provided thereto if necessary.

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する磁気記録媒体に関する
ものである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic recording medium suitable for high-density magnetic recording.

（従来例の構成とその問題点） 近年の磁気記録の高密度化の進歩は著しく、従来の延長
線上にはもはやこれ以上の高密度化を望むことは困難な
状況になっている。従って、ｃ。(Structure of conventional example and its problems) The progress in increasing the density of magnetic recording has been remarkable in recent years, and it is no longer possible to hope for higher densities as an extension of conventional methods. Therefore, c.

を吸着させたｒ−Ｆｓ２０３微粒子とバインダを主成分
とする磁気記録層から、バインダをもたずかつ酸化物磁
性体の飽和磁束密度の低さを解消する強磁性金属薄膜を
磁気記録層とする磁気記録媒体への転換が期待されてい
る。From a magnetic recording layer mainly composed of r-Fs203 particles adsorbed with a binder, a ferromagnetic metal thin film that does not have a binder and eliminates the low saturation magnetic flux density of oxide magnetic material is used as a magnetic recording layer. A shift to magnetic recording media is expected.

強磁性金属薄膜型磁気記録媒体は第１図に示すように１
高分子基板１上に強磁性金属薄膜２を配し、実用性能を
向上させるために、保護層３と、バックコート層４を配
したものが一般的である。The ferromagnetic metal thin film type magnetic recording medium has 1 as shown in Figure 1.
Generally, a ferromagnetic metal thin film 2 is disposed on a polymer substrate 1, and a protective layer 3 and a back coat layer 4 are disposed in order to improve practical performance.

最近磁化容易軸が膜面に垂直な場合、強磁性金属薄膜と
高分子基板の中間に軟磁性層を配し、記録再生特性を改
良したものが知られているが、磁化容易軸の方向罠無関
係に、−軸異方性の良好な薄膜が磁気記録に適している
と考えられ、製法上も工夫をこらして、保磁力の大きな
、磁化特性の角形性の良好な薄膜を形成する努力がなさ
れている。Recently, it is known that when the easy axis of magnetization is perpendicular to the film surface, a soft magnetic layer is placed between the ferromagnetic metal thin film and the polymer substrate to improve the recording and reproducing characteristics. Regardless, thin films with good -axis anisotropy are thought to be suitable for magnetic recording, and efforts are being made to form thin films with large coercive force and good squareness of magnetization characteristics by devising manufacturing methods. being done.

現状ではリング型磁気ヘッドで長手記録媒体による記録
再生が信号対雑音比（Ｓ＄）からみて、最もすぐれてい
るが、長手記録では、記録波長を短かくしていくと、損
失が大きくなり、Ｓ／Ｎが確保できなくなるので、面積
記録密度を大きくするためにトラック幅を狭くするのが
得策である。Currently, recording and reproducing using a longitudinal recording medium using a ring-type magnetic head is the best in terms of signal-to-noise ratio (S$), but in longitudinal recording, as the recording wavelength becomes shorter, the loss increases and the S/ Since N cannot be secured, it is advisable to narrow the track width in order to increase the areal recording density.

しかし−軸異方性の良好な膜で保磁力を８００　（６ｅ
　）から１６００（Ｏｓ）までの範囲で変化させて、記
録再生すると、Ｓハとしては必ずしも満足できないこと
が明らかになった。However, a film with good -axis anisotropy has a coercive force of 800 (6e
) to 1600 (Os) and recorded and reproduced, it became clear that S was not necessarily satisfactory.

（発明の目的） 本発明の目的は、従来の欠点を解消し、狭トラツク記録
再生でのＳ／Ｎの改良された磁気記録媒体を提供するこ
とである。(Objective of the Invention) An object of the present invention is to eliminate the conventional drawbacks and provide a magnetic recording medium with an improved S/N ratio in narrow track recording and reproduction.

（発明の構成） 本発明の磁気記録媒体は、強磁性薄膜の保磁力の長手方
向の値と′、長手と直交方向の値の比が１．８から３，
０の範囲にあるものである０（実施例の説明） 本発明の一実施例を第２図に基づいて説明する。(Structure of the Invention) The magnetic recording medium of the present invention is characterized in that the ratio of the coercive force of the ferromagnetic thin film in the longitudinal direction and the value in the direction perpendicular to the longitudinal direction is from 1.8 to 3.
0 (Explanation of Embodiment) An embodiment of the present invention will be described based on FIG. 2.

同図はＶ、Ｓ、Ｍ、で測定したヒステリシス曲線の一例
で、Ｈｅ（ＩＪが長手方向の保磁力、Ｈ（２）が長手と
直交方向の保磁力で、本発明の磁気記録層は１．８≦Ｈ
ｅ（１）／　Ｈｅ（２）≦３．０の関係を満足する構成
であればよく、材質には無関係である０ 本発明の磁気記録媒体は、基本的に高密度記録を目指す
ものであるからＨｅ（１）／　Ｈｅ（２）の関係が上記
の範囲であれば、全て良いということはないのは当然で
、公知のようにＨｅ（１）が５００（Ｏｅ）で、たとえ
ば０．７μｍを十分なＳハで再生できないことは明らか
で、７（１０（Ｏｓ）から８００（５ｅ）のＨｅ（１）
は最低限確保しないと１μｍ以下での記録波長で４５ｄ
Ｂ以上のＳ／Ｎをトラック幅２０μｍで確保できないの
で、Ｈｅ（１）は必要な大きさを確保した前提で本発明
は構成されるものである。The figure shows an example of a hysteresis curve measured at V, S, and M, where He (IJ is the coercive force in the longitudinal direction, H (2) is the coercive force in the direction perpendicular to the longitudinal direction, and the magnetic recording layer of the present invention is 1 .8≦H
Any configuration is sufficient as long as it satisfies the relationship e(1)/He(2)≦3.0, and is unrelated to the material.0 The magnetic recording medium of the present invention basically aims at high-density recording. Therefore, if the relationship between He(1)/He(2) is within the above range, it is natural that not everything is good. It is clear that it cannot be reproduced with sufficient S Ha, and He (1) of 7 (10 (Os) to 800 (5e)
is 45d at a recording wavelength of 1μm or less unless the minimum is ensured.
Since it is not possible to secure an S/N of B or higher with a track width of 20 μm, the present invention is constructed on the premise that He(1) has the necessary size.

Ｈｅ（１）／　Ｈｅ（２）の臨界的意義については、い
の目標を４５　ｄＢ以上とし、記録波長０．７５μｍ、
）ラック幅９μｍが実現できる磁気記録システムが超小
型ビデオシステムを可能にする数値目標として評価した
ときに生じた限定である。Regarding the critical significance of He(1)/He(2), we set a target of 45 dB or more, a recording wavelength of 0.75 μm,
) This is a limitation that arose when a magnetic recording system that could realize a rack width of 9 μm was evaluated as a numerical goal that would enable an ultra-compact video system.

１．８以下になると長手と直交方向の磁気的擾乱が、雑
音となり無視できなくなり、３．０以上だと一軸異方性
が強くなり、磁化遷移領域の、のこぎυ歯状の乱れが、
雑音成分として大きくなるため、臨界が生じていると考
えられるものである。When it is less than 1.8, the magnetic disturbance in the direction orthogonal to the longitudinal direction becomes noise and cannot be ignored, and when it is more than 3.0, the uniaxial anisotropy becomes strong, and the sawtooth-like disturbance in the magnetization transition region becomes
Since the noise component becomes large, it is thought that criticality has occurred.

本発明に用いることのできる磁気記録層は、Ｃｏ。The magnetic recording layer that can be used in the present invention is Co.

Ｃｏ−Ｎｉ　　、　Ｃｏ−Ｆ＠　、、　　Ｃｏ−Ｔｌ　
　、　　Ｃｏ−Ｃｒ　　、　　Ｃｏ−Ｍｎ　。Co-Ni, Co-F@,, Co-Tl
, Co-Cr, Co-Mn.

Ｃｏ　−Ｍｇ　、　　Ｃｏ　−Ｒｕ　、　　Ｃｏ−Ｖ　
、　　Ｃｏ　−Ｍｏ　、　　Ｃｏ　−Ｎｔ　−Ｐ　。Co-Mg, Co-Ru, Co-V
, Co-Mo, Co-Nt-P.

Ｃｏ−Ｎ１−Ｚｎ−Ｐ　等およびそれらの部分酸化膜な
どで、電子ビーム蒸着法、イオンシレーティフグ法、ス
パッタリング法、無電解メッキ法等で得られるものであ
る。Co--N1-Zn-P, etc., and partially oxidized films thereof, which can be obtained by electron beam evaporation, ion silage blowing, sputtering, electroless plating, etc.

さらに具体的に一実施例について説明する。An example will be described in more detail.

厚さ１０．５μｍのポリエチレンテレフタレートフィル
ム上に、直径約１９０１の５ｉｎ２粒子をポリエステル
樹脂で固定した。樹脂の実効厚さは７０Ｘとした。８１
０２粒子は１μｍ　Ｘ　ｌ　ｌ１ｍに平均６個とした。5in2 particles with a diameter of about 1901 were fixed with polyester resin on a polyethylene terephthalate film with a thickness of 10.5 μm. The effective thickness of the resin was 70X. 81
The average number of 02 particles was 6 per 1 μm x 1 m.

この基板を用い、直径１．２　ｍの円筒状キャンに沿わ
せて連結入射角変化蒸着法でＣｏ−Ｎ１　（Ｎｌ　２０
ｗｔ％　）を４Ｘ１０−５Ｔｏｒｒの酸素中で電子ヒー
ム蒸着を行なった。電子ビームの集束状態と走査波形と
最小入射角の調整によりＨｅ（１）とＨｅ　（２）の各
種の値のものを準備した。Using this substrate, Co-N1 (Nl 20
wt%) was subjected to electron beam evaporation in oxygen at 4×10 −5 Torr. Various values of He(1) and He(2) were prepared by adjusting the focusing state of the electron beam, the scanning waveform, and the minimum incident angle.

磁気記録層の厚さは０．１５μｍ一定とし、得られた磁
気テープのＳ／ＮをＣＯ系非晶質合金リング型磁気ヘッ
ド（ギャップ長０．２５μｍ）による記録再生で測定し
た。The thickness of the magnetic recording layer was kept constant at 0.15 μm, and the S/N of the obtained magnetic tape was measured by recording and reproducing using a CO-based amorphous alloy ring-type magnetic head (gap length 0.25 μm).

記録波長は０．７５μｍ、）ラック幅は９μｍとした。The recording wavelength was 0.75 μm, and the rack width was 9 μm.

得られた媒体条件とＳ／Ｎを表に示す。The obtained medium conditions and S/N are shown in the table.

表よシ、本発明の強磁性薄膜の要件であるＨｃ　（１）
／　Ｈｅ（２）が１．８から３．０までの範囲では狭ト
ラツク、短波長による高密度記録でも４５ｄＢ以上のＳ
ハが確保できることがわかる。Table 1. Hc (1), which is a requirement for the ferromagnetic thin film of the present invention.
/ In the He(2) range of 1.8 to 3.0, even narrow tracks and high-density recording with short wavelengths can achieve S of 45 dB or more.
It can be seen that Ha can be secured.

表 （発明の効果） 本発明によれば、磁気記録媒体休の長手方向の保磁力と
、長手と直交する方向の保磁力の比を１．８から３．０
の範囲にとった強磁性薄膜を磁気記録層とすることで、
リング型磁気ヘッドによる高密度記録再生時のＳ／ｆ’
、ｌを改良できるもので、その実用的効果は大である。Table (Effects of the Invention) According to the present invention, the ratio of the coercive force in the longitudinal direction of the magnetic recording medium to the coercive force in the direction orthogonal to the longitudinal direction is 1.8 to 3.0.
By using a ferromagnetic thin film in the range of as a magnetic recording layer,
S/f' during high-density recording and reproduction using a ring-type magnetic head
, l can be improved, and its practical effects are great.

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

第１図は磁気記録媒体の拡大断面図、第２図は強磁性金
属薄膜の長手方向および長手と直交する方向のヒステリ
ラス曲線の一例である。 １・・・高分子基板、２・・・強磁性金属薄膜、３・・
・保護層、４・・・バックコート層。 特許出願人　　松下電器産業株式会社 第１図 第２図FIG. 1 is an enlarged cross-sectional view of a magnetic recording medium, and FIG. 2 is an example of a hysteresis curve in the longitudinal direction of a ferromagnetic metal thin film and in a direction orthogonal to the longitudinal direction. 1... Polymer substrate, 2... Ferromagnetic metal thin film, 3...
- Protective layer, 4... back coat layer. Patent applicant: Matsushita Electric Industrial Co., Ltd. Figure 1 Figure 2

Claims (1)

【特許請求の範囲】[Claims] 強磁性薄膜を磁気記録層とし、該強磁性薄膜の保磁力の
長手方向と長手と直交方向の比が１．８から３．０の範
囲にあることを特徴とする磁気記録媒体。1. A magnetic recording medium comprising a ferromagnetic thin film as a magnetic recording layer, the ferromagnetic thin film having a ratio of coercive force in a longitudinal direction to a direction orthogonal to the longitudinal direction in the range of 1.8 to 3.0.