JPS63119015A - Perpendicular magnetic recording medium - Google Patents

Abstract

PURPOSE:To permit high-density recording by providing a perpendicularly magnetized film having <=6X10<5>erg/cc size of unidirectional anisotropy constant to a titled medium. CONSTITUTION:This recording medium has the perpendicularly magnetized film having <=6X10<5>erg/cc size of the unidirectional anisotropy constant. The recording by a magnetic head is difficult and the recording medium having small reproduction output at the high density is eventually obtd. if the size of the unidirectional anisotropy is large. More specifically, the recording medium having large D50 (recording density at which the output of 1/2 the output at a low recording density is obtd.) is obtd. in the case of using the perpendicularly magnetized film having the small size of the unidirectional anisotropy. The easy recording to the recording medium by the magnetic head is permitted by specifying the size of the unidirectional anisotropy of the perpendicularly magnetized film to <=6X10<5>erg/cc and the high D50 value is eventually obtd. with high reproducibility.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は磁気記録媒体に係り、とくに高密度磁気記録に
適した垂直磁気記録媒体中の垂直磁化膜釦関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium, and particularly to a perpendicular magnetization film button in a perpendicular magnetic recording medium suitable for high-density magnetic recording.

〔従来の技術〕[Conventional technology]

垂直磁気記録方式は高密度記録に適した方法として知ら
れておシ、アイ・イー・イー・トランザクション　オン
　マクネテイツクス、エム　エージ−（Ｉ　ＥＥＥ　　
ｒｒａｎｓ　、　ｏｎ　Ｍａｇｎｅｔｉｃｓ　、　ＭＡ
Ｇ　）２１（１９８５年）第１４２６頁から第１４２８
頁において論じられているように、適当な垂直磁気異方
性を有する垂直磁化膜を用いることにより−Ｄｓ。Perpendicular magnetic recording is known as a method suitable for high-density recording.
rrans, on Magnetics, MA
G) 21 (1985) pp. 1426-1428
-Ds by using perpendicularly magnetized films with appropriate perpendicular magnetic anisotropy, as discussed in p.

（低記録密度における出力の１／２の出力を得る記録密
度）として２００ｋＰＣＩ以上の記録密度を得ることが
できる。(Recording density for obtaining 1/2 output of output at low recording density) A recording density of 200 kPCI or more can be obtained.

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

本発明者等は、垂直磁気記録媒体用垂直磁化膜としてＣ
ｏ−ＣｒＷＬを用い、従来使用されている磁気特性（飽
和磁化、垂直方向保磁力、面内方向保磁力）と記録再生
特性の関係を調べたところ、はぼ同一の磁気特性のＣｏ
−Ｃｒ膜を用いた場合でも記録再生特性は必ずしも同一
にはならないことを見出した。The present inventors have proposed C as a perpendicular magnetization film for perpendicular magnetic recording media.
When we investigated the relationship between the conventionally used magnetic properties (saturation magnetization, perpendicular coercive force, in-plane coercive force) and recording and reproducing properties using o-CrWL, we found that Co has almost the same magnetic properties.
It has been found that even when a -Cr film is used, the recording and reproducing characteristics are not necessarily the same.

このばらつきの原因を検討する中で本発明者等は、記録
再生特性に影響を及ぼす新たな因子を見出し、この因子
の大きさを制御することにより常に良好な記録再生特性
が得られることをあきらかにした。In examining the causes of this variation, the inventors discovered a new factor that affects recording and reproducing characteristics, and demonstrated that good recording and reproducing characteristics can always be obtained by controlling the magnitude of this factor. I made it.

本発明の目的は高密度記′ａを可能とした磁気記録媒体
を提供することにある。An object of the present invention is to provide a magnetic recording medium that enables high-density recording.

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

上記目的を達成する九めＫ、本発明によれば、一方向異
方性定数を大きさが６ｘｌＯ’　ｅｒｇ／ｃｃ以下であ
る垂直磁化膜を有して構成される。According to the present invention, a perpendicularly magnetized film having a unidirectional anisotropy constant of 6xlO' erg/cc or less is provided.

〔作用〕[Effect]

本発明者等はＣｏ−Ｃｒ膜の磁気異方性を詳しく検討す
ることによシ、Ｃｏ−Ｃｒ１ｌＬの磁気異方性には従来
知られていたｓｉｇｈ”θあるいはｓｉｎ　’θ（θは
磁化容易軸と磁化の方向とのなす角度）に比例する一軸
異方性の項の他に、−Ｃｏｇθに比例する一方向異方性
が存在することを見出した。By studying the magnetic anisotropy of the Co-Cr film in detail, the present inventors discovered that the magnetic anisotropy of Co-Cr11L has the previously known sig" θ or sin' θ (θ is easy to magnetize. It has been found that in addition to the uniaxial anisotropy term proportional to the angle between the axis and the direction of magnetization, there is a unidirectional anisotropy term proportional to -Cogθ.

まずこの一方向異方性について説明する。−方向異方性
が存在する場合のエネルギー密度は次式のように書ける
。First, this unidirectional anisotropy will be explained. The energy density when −direction anisotropy exists can be written as the following equation.

Ｅ　ａ　＝　Ｋ　（１”θ＋Ｋ　ｔ　５ｉｌｌ雪θ＋Ｋ
１５ｕ’θ　Ｉ　＠）（ｉｓ　（θ−α）ここで、Ｉｓ
、Ｈはそれぞれ飽和磁化および外部磁界の大きさであり
、αは磁化容易軸と外ｇａ界の方向とのなす角度である
。E a = K (1”θ+K t 5ill snow θ+K
15u'θ I @)(is (θ-α) where Is
, H are the saturation magnetization and the magnitude of the external magnetic field, respectively, and α is the angle between the axis of easy magnetization and the direction of the external ga field.

従来、アイ・イー・イー・イー・トランザクション　オ
ン　マクネテイツクス、エム・ニー・ジー（Ｉ　ＥＫＥ
　Ｔｒａｎｓ、　ｏｎ　Ｍａｇｎａｔｉｃｓ、　ＭＡＧ
）１６（１９８０年）第１１１１頁から第１１１３頁に
おいて述べられているように、Ｃｏ−Ｃｒ膜のトルク曲
線の解祈はＫｏ　＝Ｋｚ　＝Ｏとして考えられてきた。Traditionally, IEE Transactions on Macnetics, MNE
Trans, on Magnetics, MAG
) 16 (1980), pages 1111 to 1113, the solution of the torque curve of a Co--Cr film has been considered as Ko = Kz = O.

実験によ少得られたトルク曲ａｔフーリエ展開し＠　３
１１２αに比例する項の大きさｔ”　Ａ　ｓとする。Torque curve obtained by experiment at Fourier expansion @ 3
Let the magnitude of the term proportional to 112α be t” A s.

Ｋｏ　＝Ｋｓ　＝０でありＩｍＨ＞Ｋｓの場合には、Ａ
Ｉは外部磁界の大きさには依存しない一定値（＝−Ｋｌ
／２）になるはずである。If Ko = Ks = 0 and ImH > Ks, then A
I is a constant value that does not depend on the magnitude of the external magnetic field (=-Kl
/2).

−万、Ｃｏ−Ｃｒ膜のトルク曲線よ）求めた人１社第１
図に示す二うに、１／ｉ（に対し一次の関係にある。こ
のＡｌの１／Ｈに対する傾きは。-10,000, Co-Cr film torque curve) 1st company and 1st person
As shown in the figure, there is a linear relationship with 1/i (.The slope of this Al with respect to 1/H is.

Ｋ３を考慮しても充分説明することは出来ない。Even if K3 is considered, it cannot be fully explained.

そこで、第１図、第２図に示すように、一方向異方性の
項一に、　ｏｎｓ　ｅ　ｔ−導入したところ、ＡＩの外
部磁界依存性のみならず、トルク曲線をフーリエ展開し
て得た５ｉ１４αに比例する項五３の外部磁界依存性を
もほぼ説明しうろことがわかった。この一方向異方性は
結晶粒中のＣｒ反強磁性層と同じく結晶粒中のＣｏ−Ｃ
ｒ強磁性層の間の交換相互作用により生じると考えてい
る。Therefore, as shown in Fig. 1 and Fig. 2, when we introduce unidirectional anisotropy into the term 1, not only the external magnetic field dependence of AI but also the torque curve obtained by Fourier expansion. It was found that the dependence of the term 53, which is proportional to 5i14α, on the external magnetic field can also be almost explained. This unidirectional anisotropy is similar to the Cr antiferromagnetic layer in the crystal grains, as well as the Co-C in the crystal grains.
It is believed that this is caused by exchange interaction between r ferromagnetic layers.

この一方向異方性の大きさが太き一場合には。If the magnitude of this unidirectional anisotropy is large.

磁気ヘッドによる記録が困ＪｌｉＫなシ、その結果。As a result, recording with a magnetic head is difficult.

高密度における再生出力が小さな記録媒体になる。A recording medium with a small reproduction output at high density.

すなわち、一方向異方性の大きさの小さな垂直磁化膜を
用いた場合にはＤｉｅの大きな記録媒体となる。That is, when a perpendicularly magnetized film with a small unidirectional anisotropy is used, a recording medium with a large Die can be obtained.

垂直磁化膜の一方向異方性の大きさを６×１０５ｅｒｇ
／ｃｃ以下の大きさとすることにより、磁気ヘッドによ
る記録媒体への記録を容易にし、その結果、再現性良く
高−Ｄｉｅ値を得ることが可能となった。The size of the unidirectional anisotropy of the perpendicular magnetization film is 6×105erg.
By making the size smaller than /cc, it becomes easier to record on the recording medium by the magnetic head, and as a result, it becomes possible to obtain a high -Die value with good reproducibility.

〔実施例〕〔Example〕

以下１本発明を実施例によシ詳しく説明する。 The present invention will be explained in detail below using examples.

実施例１ ポリイミド基板上にスパッタ法によシ膜厚α２μｍのＣ
０５ｏ　Ｃｒ５ｏ膜を作製した。スパッタ時の基板温度
は７０Ｃ，Ａｒ圧は３　Ｘ　１０−”　Ｔｏｒｒ　。Example 1 A film of C with a thickness α of 2 μm was deposited on a polyimide substrate by sputtering.
A 05o Cr5o film was prepared. The substrate temperature during sputtering was 70 C, and the Ar pressure was 3 x 10-'' Torr.

ａｌｌ’［力密度は０．４Ｗ／ｃｍ”とし、スバｙｐ中
は膜厚垂直方向にθ〜５０００ｅの磁界を印加した。all'[The force density was 0.4 W/cm'', and a magnetic field of θ˜5000 e was applied in the direction perpendicular to the film thickness during the vacuum p.

第３図にスパッタ中の印加磁界の大きさと一方向異方性
定数Ｋｏの関係を示す。同図よシ印加磁界の増加に伴い
Ｋｏが増大することがわかる。FIG. 3 shows the relationship between the magnitude of the magnetic field applied during sputtering and the unidirectional anisotropy constant Ko. It can be seen from the figure that Ko increases as the applied magnetic field increases.

上述の試料と、ギャップ部に飽和磁束密度１０４ＧのＣ
ｏＮｂＺｒ１ｌＥｔ−挿入したＭ　ｎ　Ｚ　ｎフェライ
トヘッドを用φて記録再生実ｌＩＬを行なった。これら
のディスクの保磁力は４５０〜４８００ｅ、面内方向保
磁力は１３０〜１５００６　、飽和磁化の大きさは２８
０〜３１００ｅとほぼ一定値である。これらのディスク
のＫｏ値とＤｓｏの関係を第４図に示す。The above sample and C with a saturation magnetic flux density of 104G in the gap part.
oNbZr11Et-Recording/reproduction was performed using the inserted MnZn ferrite head. The coercive force of these disks is 450-4800e, the in-plane coercive force is 130-15006, and the magnitude of saturation magnetization is 28
The value is approximately constant from 0 to 3100e. FIG. 4 shows the relationship between the Ko value and Dso of these disks.

同図よυｈＫｏが大きくなるとＤＢは小さくなること、
また、Ｄｓｏ）２００ｋＦＣＩｔ”得るためには。As shown in the same figure, as υhKo increases, DB decreases.
Also, in order to obtain ``Dso) 200kFCIt''.

ＫＯが６ｘ　１　Ｇ’　ｅｒｇ／ｃｃ以下テナケレハナ
ラナいことがわかる。It can be seen that the KO is less than 6x 1 G'erg/cc.

〔発明の効果〕〔Effect of the invention〕

以上述べてきたように１本発明によれば、Ｋ。 As described above, according to the present invention, K.

ｔ６Ｘ　１０’ｅｒｇ／ｃｃ以下としたものであるから
高記録密度を達成することができる。Since t6X is 10'erg/cc or less, high recording density can be achieved.

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

Claims (1)

【特許請求の範囲】[Claims] １、一方向異方性定数の大きさが６×１０＾５ｅｒｇ／
ｃｃ以下である垂直磁化膜を有することを特徴とする垂
直磁気記録媒体。1. The size of the unidirectional anisotropy constant is 6×10^5erg/
A perpendicular magnetic recording medium characterized by having a perpendicular magnetization film having a perpendicular magnetization of cc or less.