JPS5847767B2 - Jikihed - Google Patents

Description

【発明の詳細な説明】 本発明は磁気抵抗効果素子を用いた薄膜形磁気ヘッドの
改良に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a thin film magnetic head using a magnetoresistive element.

従来、パーマロイ、センダスト、フエライト等の強磁性
材料からなるコア一部分を空Ｌ ＳｉＯ ，ＣｕやＡＩ
等の非磁性部分からなる空隙部を介して対向させ、前記
コア一部分の一部にＡＩやＣｕ等の導電性材料からなる
巻線を巻きつけた巻線部を有した磁気ヘッドが用いられ
ていたが、これとは異なるタイプとして最近パーマロイ
、センダストやフエライト等の強磁性材別で磁気抵抗効
果を有した材別に前記磁性記録媒体からの磁束が通ると
き、この磁束と前記強磁性材別中のスピンとの相互作用
に伴う電気抵抗の変化を前記媒体からの記録信号として
読み出す磁気ヘッド（磁気抵抗効果型磁気ヘッド、以下
単にＭＲヘッドという）が考えられている。Conventionally, a portion of the core made of ferromagnetic materials such as permalloy, sendust, and ferrite was used as an empty L, such as SiO, Cu, or AI.
A magnetic head is used, which has a winding part in which a winding made of a conductive material such as AI or Cu is wound around a part of the core part, and the winding part is made of a conductive material such as AI or Cu. However, when the magnetic flux from the magnetic recording medium passes through a different type of ferromagnetic material, such as permalloy, sendust, and ferrite, which has a magnetoresistive effect, this magnetic flux and the ferromagnetic material have a different effect. A magnetic head (magnetoresistive magnetic head, hereinafter simply referred to as MR head) that reads out changes in electrical resistance due to interaction with the spin of the medium as a recording signal from the medium has been considered.

まず、はじめにＭＲヘッドの基本動作、基本構成を第１
図〜第３図とともに説明する。First, we will explain the basic operation and configuration of the MR head in the first part.
This will be explained with reference to FIGS.

容易方向がｙ方向で一軸異方性を示すパーマロイ等の強
磁性からなる磁気抵抗効果素子（以下、単にＭＲ素子と
いう）１に磁性記録媒体から漏洩した磁束のＸ戒分Φｒ
ｘがｘ − ｙ面のＸ方向を通過するときＭＲ素子１の
磁化Ｍｓはエネルギーの極小条件を満たすようにＸ方向
と角度θをなす方向に向くために、ＭＲ素子１のＸ方向
における比抵抗ρはＭＲ素子１にΦｒｘが通過しない時
の比抵抗をρ０とするとρ一ρＱ （Ｘ−ＣＯＳ ２θ
のように変化する。X fraction Φr of the magnetic flux leaked from the magnetic recording medium to the magnetoresistive element (hereinafter simply referred to as MR element) 1 made of ferromagnetic material such as permalloy whose easy direction is the y direction and exhibits uniaxial anisotropy.
When x passes through the X direction of the x-y plane, the magnetization Ms of the MR element 1 is oriented in a direction forming an angle θ with the X direction so as to satisfy the minimum energy condition, so the specific resistance of the MR element 1 in the X direction is ρ is ρ−ρQ (X−COS 2θ
It changes like this.

したがって、ＭＲ素子１０両端部１１．１２にＡＩ，Ｃ
ｕやパーマロイ等からなる導電性材利２を接続させてＭ
Ｒ素子１中のＸ方向に直流の電流を流すと、記録媒体か
らの記録信号に応じてＭＲ素子１の１１．１２の間で電
圧変化つまり出力Ｅを第２図に示すように取り出すこと
ができる。Therefore, AI, C at both ends 11.12 of the MR element 10
M by connecting conductive material 2 made of u or permalloy etc.
When a direct current is passed in the X direction in the R element 1, a voltage change between 11 and 12 of the MR element 1 according to the recording signal from the recording medium, that is, an output E can be taken out as shown in Figure 2. can.

なお、第２図におけるμはＭＲ素子１の透磁率を示す。Note that μ in FIG. 2 indicates the magnetic permeability of the MR element 1.

ＭＲヘッドは原理上出力Ｅを大きくするために、ＭＲ素
子１には厚みが薄いことが要求されるので蒸着、スパッ
タリング等の技術を用いてＭＲ素子１を作製する。In order to increase the output E of the MR head in principle, the MR element 1 is required to be thin, so the MR element 1 is manufactured using techniques such as vapor deposition and sputtering.

また、ＭＲ素子１の有する磁気的異方性が悪いと第３図
に示すようなヒステリシス現象が生じ、さらに第２図、
第３図における最大出力Ｅｍａｘが低下するので、ＭＲ
素子１には磁気的に分散の少ない一軸異方性が要求され
、容易軸を直流電流ｉと直交させ、この電流方向に記録
信号に伴う磁束Φｒｘを通過させる方法が行われている
。Furthermore, if the magnetic anisotropy of the MR element 1 is poor, a hysteresis phenomenon as shown in FIG. 3 occurs, and furthermore, as shown in FIG.
Since the maximum output Emax in Fig. 3 decreases, MR
The element 1 is required to have uniaxial anisotropy with little magnetic dispersion, and a method is used in which the easy axis is made perpendicular to the direct current i and the magnetic flux Φrx associated with the recording signal is passed in the direction of this current.

出力Ｅと印加磁場Ｈは非線形の領域を含んでいるために
、所要のバイアス直流磁界Ｈｂを記録媒体からの記号ａ
に加えることによって、第２図に示すように動作点Ｐ点
に移動させ、線形領域を利用して、記録信号ａを信号ｂ
のように取り出している。Since the output E and the applied magnetic field H include a nonlinear region, the required bias DC magnetic field Hb is expressed by the symbol a from the recording medium.
As shown in FIG. 2, the recording signal a is moved to the operating point P by adding
It is taken out like this.

このような動作方法はアナログ信号の読み出しにおいて
も有効的な方法である。Such an operating method is also effective in reading analog signals.

従来、バイアス直流磁界Ｈｂを与えるために、第４図〜
第７図に示すようにＭＲ素子１に２方向のバイアス直流
磁界Ｈｂを印加するためにＡＩ，パーマロイ等の導電性
材利からなるワイヤー３あるいは帯状体４にバイアス直
流電流ｉ，を流していた。Conventionally, in order to apply a bias DC magnetic field Hb, the method shown in FIGS.
As shown in FIG. 7, in order to apply a bias DC magnetic field Hb in two directions to the MR element 1, a bias DC current i was passed through a wire 3 or a strip 4 made of a conductive material such as AI or permalloy. .

しかしながら、この場合、素子１の全域にわたって一様
な大きさのバイアス磁界が得にくい。However, in this case, it is difficult to obtain a bias magnetic field of uniform magnitude over the entire area of the element 1.

これを避ける方法としてたとえば第７図に示された帯状
体４のＸ方向における長さｔ２と素子の長さｔ１とをｔ
２〉ｔ１の条件に設定する方法が考えられる。To avoid this, for example, the length t2 of the strip 4 in the X direction and the length t1 of the element shown in FIG.
A possible method is to set the condition to 2>t1.

しかし、ＭＲ素子１を動作中常時バイアス直流電流ｉｂ
を流す必要が有するために電力消費が大きく、コスト面
で問題が生じる。However, when the MR element 1 is in operation, the constant bias DC current ib
This requires high power consumption, which poses a cost problem.

さらに重要な問題として導電性物質３，４に直流電流ｉ
ｂが流れることにより生じるジュール熱がＭＲ素子１に
加わり、ＭＲ素子１の磁気特性を低下させる。An even more important issue is the direct current i in the conductive materials 3 and 4.
Joule heat generated by the flow of b is applied to the MR element 1, reducing the magnetic properties of the MR element 1.

さらに他の従来例として、第８図に示すように、バルク
状の永久磁石４１をネジ４２でｙ方向に動かすことによ
って、素子１にバイアス直流磁界をを加える方法がある
が、永久磁石４１を所要の形状に作製するための機械的
加工工程が必要であり、ＭＲ素子１と一体に作製したり
、加工したりすることができない。As another conventional example, there is a method of applying a bias DC magnetic field to the element 1 by moving a bulk permanent magnet 41 in the y direction with a screw 42, as shown in FIG. A mechanical processing step is required to manufacture it into a desired shape, and it cannot be manufactured or processed integrally with the MR element 1.

さらに、永久磁石には機械的加工が困難な材料もあって
材料の選択が要求されたり、またＭＲ素子１に所要のバ
イアス直流磁界を与えるにあたり機械的な調整方法つま
りネジ４２で調整しているために微調整が困難である。Furthermore, permanent magnets include materials that are difficult to process mechanically, so selection of the material is required, and in order to provide the required bias DC magnetic field to the MR element 1, a mechanical adjustment method, that is, adjustment using the screw 42, is required. Therefore, fine adjustment is difficult.

本発明の磁気ヘッドは直流バイアス磁界Ｈｂにおける以
上の問題を解決するものである。The magnetic head of the present invention solves the above problems in the DC bias magnetic field Hb.

以下、本発明の実施例について第９図〜第１１図を用い
て説明する。Embodiments of the present invention will be described below with reference to FIGS. 9 to 11.

これらの図において、磁気ヘッドは磁気抵抗効果型であ
り、ガラス、セラミック、ステンレス鋼、シリコン等の
非磁性材料からなる基板５上に蒸着、スパッタリングや
電着等の技術を用いて以下の構或の膜を作製し、フォト
エッチング、エレクトロフオーミング等の技術を用いて
微細な構或を形威している前記基板５上に（第９図では
ｘ − ｙ面の２方向）右側磁性薄膜６１、左側磁性薄
膜６２を、空隙長さがｇで空気、Ｃｕ ， ＡＩ ，
ＳｉＯ等の非磁性部分からなる空隙部７を介して、対向
させ、前記薄膜６１ ．６２の記録媒体１７と離れた位
置において長手方向（第９図ではＸ方向）の長さがｔ３
、幅方向（同じくｙ方向）の長さがＷ３のパーマロイ薄
膜等の強磁性薄膜からなるＭＲ素子９を前記薄膜６１
．６２と磁気的に橋絡させ、前記薄膜６１．６２とＭＲ
素子９で閉じた磁気回路を形或させる。In these figures, the magnetic head is of a magnetoresistive type, and is fabricated using techniques such as vapor deposition, sputtering, and electrodeposition on a substrate 5 made of non-magnetic material such as glass, ceramic, stainless steel, and silicon. A right side magnetic thin film 61 is formed on the substrate 5 (in the two directions of the x-y plane in FIG. 9) on which a fine structure is formed using techniques such as photo-etching and electroforming. , the left magnetic thin film 62 is made of air, Cu, AI, with a gap length of g.
The thin films 61 . The length in the longitudinal direction (in the X direction in FIG. 9) at a position away from the recording medium 17 of 62 is t3.
, an MR element 9 made of a ferromagnetic thin film such as a permalloy thin film having a length W3 in the width direction (also in the y direction) is attached to the thin film 61.
．． 62 and magnetically bridged with the thin film 61.62 and MR.
The element 9 forms a closed magnetic circuit.

なおＭＲ素子９の下部には長手方向（第９図ではＸ方向
）の長さが少なくともＭＲ素子９よりも小さくない、Ｓ
ｉＯ，ＳｉＯ２，ＭｇＯ等の非磁性材料からなるまくら
部分２１を配する。Note that at the bottom of the MR element 9 there is an S whose length in the longitudinal direction (in the X direction in FIG. 9) is at least not smaller than the MR element 9.
A pillow portion 21 made of a non-magnetic material such as iO, SiO2, MgO, etc. is provided.

次に、右側磁性薄膜６１および左側磁性薄膜６２の一部
分８Ｌ８２の上部にＡＩ，ＣＬＩ，パーマロイ等の導電
性材料からなる電流取出部分１３．１４を配し、直流電
流ｉをＭＲ素子９に流す。Next, current extraction portions 13 and 14 made of a conductive material such as AI, CLI, permalloy, etc. are placed above the right magnetic thin film 61 and the portion 8L82 of the left magnetic thin film 62, and direct current i is caused to flow through the MR element 9.

さらに、ＭＲ素子９の上部（第９図および第１０図では
２方向）に空隙長さｔい空隙深さＷ４を有し閉じた磁気
回路を形成していてＳｍ−Ｃｏ系、Ｇｄ−Ｃｏ系、Ｃ
ｏ − Ｐ系等の永久磁石材料からなる永久磁石膜１６
をガラス、セラミック、ステンレス鋼、シリコン等の保
護基板１９上に形成させ、保護基板１９と前記基板５を
対向させ、永久磁石膜１６の空隙部１５（第９図の斜線
部の六方体ＥＦＧＨＩＪＫＬ）内に対向した基板５上の
ＭＲ素子９が少なくとも位置するように永久磁石膜１６
を配している。Furthermore, the upper part of the MR element 9 (in two directions in FIGS. 9 and 10) has a gap length t and a gap depth W4, forming a closed magnetic circuit, and is based on Sm-Co and Gd-Co systems. , C
Permanent magnet film 16 made of permanent magnet material such as o-P system
is formed on a protective substrate 19 made of glass, ceramic, stainless steel, silicon, etc., and the protective substrate 19 and the substrate 5 are made to face each other, and the gap 15 of the permanent magnet film 16 (the hexagonal EFGHIJKL in the shaded area in FIG. 9) is formed. The permanent magnet film 16 is arranged such that at least the MR element 9 on the opposing substrate 5 is located inside the permanent magnet film 16.
are arranged.

また、第１０図中のｔ１はＭＲ素子９の厚みを示し、ｔ
２は永久磁石膜１６の厚みを示す。Further, t1 in FIG. 10 indicates the thickness of the MR element 9, and t
2 indicates the thickness of the permanent magnet film 16.

ここで、ＭＲ素子９に一様な直流バイアス磁界Ｈｂが加
わるように’４．２ ’３ ，ｗ，，＞ｗ３の条件を満
たすようにする。Here, the conditions '4.2 '3, w, , >w3 are satisfied so that a uniform DC bias magnetic field Hb is applied to the MR element 9.

さらに、永久磁石膜１６と右側、左側磁性薄膜６１ ，
６２およびＭＲ素子９の間での電気的、磁気的な短絡を
さけるために、Ｓｉｏ ｔ Ｓｔ０２ ＋ ＭｇＯ等の
非磁性で絶縁性の膜を永久磁石膜１６の上部に配してお
く。Furthermore, the permanent magnet film 16 and the right and left magnetic thin films 61,
In order to avoid electrical and magnetic short circuits between the permanent magnet film 16 and the MR element 9, a non-magnetic and insulating film such as Siot St02 + MgO is placed on top of the permanent magnet film 16.

続いて本発明の磁気ヘッドの動作を第１１図を用いて説
明する。Next, the operation of the magnetic head of the present invention will be explained using FIG. 11.

記録媒体１７上に記録信号つまり記録された領域１８か
ら発する磁束のＸ成分Φｒｘを右側磁性薄膜６１、左側
磁性薄嘆６２によって磁気抵抗効果素子９の長手方向（
第６図および第７図ではＸ方向）に導き、さらに永久磁
石模１６によってＭＲ素子９を直流バイアス磁界Ｈｂを
記録信号と同一方向（第６図、第７図ではＸ方向）に加
え、電流取り出し部分１３．１４に直流の電流を流すと
記録信号の変化に応じた電圧変化がＭＲ素子９の長手方
向（Ｘ方向）に生じ、これを記録信号の出力Ｅとして取
り出している。The recording signal, that is, the X component Φrx of the magnetic flux emitted from the recorded area 18 on the recording medium 17 is transferred in the longitudinal direction of the magnetoresistive element 9 (
Further, a DC bias magnetic field Hb is applied to the MR element 9 using the permanent magnet pattern 16 in the same direction as the recording signal (X direction in FIGS. 6 and 7), and the current When a direct current is passed through the extraction portions 13 and 14, a voltage change occurs in the longitudinal direction (X direction) of the MR element 9 in accordance with the change in the recording signal, and this is extracted as the output E of the recording signal.

以上のように本発明の磁気ヘッドの特徴はＭＲ素子に直
流バイアス磁界Ｈｂを加える方法として、ＭＲ素子の下
部に幅方向の長手力向の長さが少なくともＭＲ素子より
も小さくないまくら部分上にＭＲ素子を配し、ＭＲ素子
が形威されている基板と対向している保護基板上に形戒
された永久磁石膜の空隙部内に前記素子が位置するよう
に構或されている点である。As described above, the feature of the magnetic head of the present invention is that as a method of applying a DC bias magnetic field Hb to the MR element, the method is to apply a DC bias magnetic field Hb to the lower part of the MR element on the pillow part whose length in the longitudinal force direction in the width direction is at least not smaller than the MR element. The MR element is arranged so that the element is located within a gap in a permanent magnet film formed on a protective substrate facing the substrate on which the MR element is formed. .

したがって、ＭＲ素子に一様なバイアス直流磁界を加え
ることができる。Therefore, a uniform bias DC magnetic field can be applied to the MR element.

さらに、本発明の磁気ヘッドの特徴としてバイアス直流
磁界を発生させるための電力を必要としないので、この
ＭＲヘッドを従来品に比べて少ない電力消費量で動作さ
せることができ、さらに従来ではバイアス直流磁界を得
るためにバイアス直流電流ｉ，を流していたので、それ
によるジュール熱が発生し、ＭＲ素子の磁気特性を劣化
させていたが、本発明の磁気ヘッドにおいては上記のジ
ュール熱による磁気特性の劣化をまぬがれることができ
る。Furthermore, since the magnetic head of the present invention does not require electric power to generate a bias DC magnetic field, this MR head can be operated with less power consumption than conventional products. In order to obtain a magnetic field, a bias DC current i was passed, which generated Joule heat and deteriorated the magnetic properties of the MR element.However, in the magnetic head of the present invention, the magnetic properties due to the Joule heat described above are reduced. deterioration can be avoided.

さらに、本発明の磁気ヘッドにおいては、保護基板上に
永久磁石膜が独立して配設され、この永久磁石膜の空隙
部内にＭＲ素子が位置するよう構或されているため、永
久磁石膜によるバイアス磁界の調整が容易で、かつ均一
なバイアス磁界をＭＲ素子に印加することができる。Furthermore, in the magnetic head of the present invention, the permanent magnet film is independently disposed on the protective substrate, and the MR element is located within the gap of the permanent magnet film. The bias magnetic field can be easily adjusted and a uniform bias magnetic field can be applied to the MR element.

したがって、特性のばらつきがきわめて少なく、安価な
薄膜型の磁気ヘッドを提供することができる。Therefore, it is possible to provide an inexpensive thin-film magnetic head with very little variation in characteristics.

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

第１図はＭＲヘッドの基本構戊の一例を示す図、第２図
および第３図はＭＲヘッドの入出力関係図、第４図、第
６図および第８図はＭＲヘッドのバイアス直流磁界を加
える方法を示す斜視図、第５図および第Ｔ図はＭＲヘッ
ドのバイアス直流磁界を加える方法の正面図、第９図は
本発明の一実施例のＭＲヘッドの要部斜視図、第１０図
および第１１図はそれぞれその要部正面図、斜視図であ
る０５・・・・・・基板、７・・・・・・空隙部、９・
・・・・・ＭＲ素子、１３．１４・・・・・・電流取出
部分、１５・・・・・・空隙部、１６・・・・・・永久
磁石膜、１７・・・・・・記録媒体、２１・・・・・・
非磁性材料まくら部分。Figure 1 is a diagram showing an example of the basic structure of an MR head, Figures 2 and 3 are input/output relationship diagrams of the MR head, and Figures 4, 6, and 8 are bias DC magnetic fields of the MR head. 5 and T are front views showing a method for applying a bias DC magnetic field to an MR head. FIG. 9 is a perspective view of essential parts of an MR head according to an embodiment of the present invention. Figure 11 is a front view and a perspective view of the main parts, respectively.
...MR element, 13.14 ... Current extraction part, 15 ... Gap part, 16 ... Permanent magnet film, 17 ... Recording Medium, 21...
Non-magnetic material pillow part.

Claims (1)

【特許請求の範囲】[Claims] １ 基板上に磁気抵抗効果素子と磁性薄膜で磁気回路を
構或し、前記基板に対向する保護基板上に形成された永
久磁石膜によって形成される空隙部内に前記磁気抵抗効
果素子を配したことを特徴とする磁気ヘッド。1. A magnetic circuit is constructed by a magnetoresistive element and a magnetic thin film on a substrate, and the magnetoresistive element is disposed within a gap formed by a permanent magnet film formed on a protective substrate facing the substrate. A magnetic head featuring: