JPH11274599A - Thin film magnetic reluctance element - Google Patents
Thin film magnetic reluctance elementInfo
- Publication number
- JPH11274599A JPH11274599A JP10111301A JP11130198A JPH11274599A JP H11274599 A JPH11274599 A JP H11274599A JP 10111301 A JP10111301 A JP 10111301A JP 11130198 A JP11130198 A JP 11130198A JP H11274599 A JPH11274599 A JP H11274599A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- magnetic
- magnetoresistive element
- soft magnetic
- thin
- 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.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y25/00—Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F10/00—Thin magnetic films, e.g. of one-domain structure
- H01F10/32—Spin-exchange-coupled multilayers, e.g. nanostructured superlattices
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、巨大磁気抵抗効果を利
用した薄膜磁気抵抗素子、およびそれを用いた磁気メモ
リー、磁気センサーおよび磁気ヘッドに関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetoresistive element utilizing a giant magnetoresistive effect, and a magnetic memory, a magnetic sensor and a magnetic head using the same.
【０００２】[0002]
【従来の技術】近年、情報の大容量化高速化に伴い、磁
気記録の分野においても、さらなる記録密度の高密度化
が進められ、垂直磁気記録方式など様々な試みがなされ
ている。磁気抵抗効果（ＭＲ）を利用した磁気ヘッド
（ＭＲヘッド）は、上記の要請に対処できるものとして
注目され、現在盛んに研究されている。またＭＲセンサ
は、磁気ヘッド以外にも、サーボモーターやロータリー
エンコダーなどの磁気センサとしても広く利用されてい
る。2. Description of the Related Art In recent years, as the capacity of information has been increased and the speed has been increased, the recording density has been further increased in the field of magnetic recording, and various attempts such as a perpendicular magnetic recording system have been made. Magnetic heads (MR heads) utilizing the magnetoresistance effect (MR) have attracted attention as being able to meet the above demands, and are being actively studied at present. In addition to the magnetic head, the MR sensor is widely used as a magnetic sensor such as a servomotor or a rotary encoder.
【０００３】このような状況の中で、従来のＭＲ材料の
１０倍以上の大きな巨大磁気抵抗効果（ＧＭＲ）を示す
材料が、Ｆｅ／Ｃｒ系などの金属人工格子膜で見出され
た（Ｍ．Ｎ．Ｂａｉｂｉｃｈ ｅｔ ａｌ，Ｐｈｙｓ．
Ｒｅｖ．Ｌｅｔｔ．６１（１９８８）２４７２）。ＧＭ
Ｒは、この発見をきっかけに金属人工格子のみならず、
Ｍｎ酸化物などの酸化物系、Ｃｏ−Ｃｕ合金などの金属
−金属系グラニュラー合金、またＣｏ−Ａｌ−Ｏ合金薄
膜などの金属−非金属系グラニュラー合金薄膜などで見
出され、現在盛んに研究されている。これらの材料は、
ＭＲ比が大きいことから、磁気ヘッドや磁気センサ等の
磁気素子への応用が期待されている。しかし、金属人工
格子のＧＭＲを利用したスピンバルブヘッドの実用化が
進められているが、耐熱性や歩留まりが悪いことなど、
問題は多い。また、金属人工格子以外のＧＭＲ材料にお
いては、磁界感度が著しく低く、磁気ヘッドや磁気セン
サ等の磁気素子に利用することは出来なかった。[0003] Under such circumstances, a material exhibiting a giant magnetoresistance effect (GMR) that is 10 times or more larger than that of a conventional MR material has been found in a metal artificial lattice film of Fe / Cr or the like (M). N. Baibich et al, Phys.
Rev .. Lett. 61 (1988) 2472). GM
R discovered that not only metal artificial lattices,
It is found in oxides such as Mn oxides, metal-metal granular alloys such as Co-Cu alloys, and metal-non-metallic granular alloy thin films such as Co-Al-O alloy thin films. Have been. These materials are
Since the MR ratio is large, application to magnetic elements such as a magnetic head and a magnetic sensor is expected. However, although spin valve heads utilizing GMR of metal artificial lattice are being put into practical use, heat resistance and yield are poor.
There are many problems. GMR materials other than metal artificial lattices have extremely low magnetic field sensitivity and cannot be used for magnetic elements such as magnetic heads and magnetic sensors.
【０００４】先に、本発明者らは、ＧＭＲ薄膜を軟磁性
薄膜と組み合わせると、ＧＭＲの磁界感度が著しく向上
することを見出し、出願した（特願平９−２７９３０８
号）。しかし、この報告では、ＭＲ比は高々４％程度で
あり、従来材料のパーマロイ（２〜３％）等と比較して
それほど特性が向上している訳ではない。[0004] The present inventors have previously found that combining a GMR thin film with a soft magnetic thin film significantly improves the magnetic field sensitivity of the GMR, and filed an application (Japanese Patent Application No. 9-279308).
issue). However, according to this report, the MR ratio is at most about 4%, and the characteristics are not so much improved as compared with a conventional material such as permalloy (2 to 3%).
【０００５】[0005]
【発明が解決しようとする課題】上記のように、ＧＭＲ
薄膜は、その応用化が期待されているにもかかわらず、
磁界感度が低いために、ＭＲ磁気センサ等の磁気素子に
用いることが出来なかった。また、軟磁性薄膜と巨大磁
気抵抗薄膜を組み合わせることによって、磁界感度は著
しく改善されるが、従来材料に比べて、より大きなＭＲ
比は得られていない。そこで、本発明者らは、弱磁界に
おいてより大きなＭＲ比を有し、磁界感度の優れた薄膜
磁気抵抗素子を得ようとするものである。As described above, the GMR
Although thin films are expected to be applied,
Due to low magnetic field sensitivity, it could not be used for magnetic elements such as MR magnetic sensors. Further, the magnetic field sensitivity is remarkably improved by combining the soft magnetic thin film and the giant magnetoresistive thin film.
No ratio has been obtained. Therefore, the inventors of the present invention intend to obtain a thin-film magnetoresistive element having a larger MR ratio in a weak magnetic field and having excellent magnetic field sensitivity.
【０００６】一方、多くの磁気センサーに用いられてい
る半導体ホール素子は、耐熱性が悪く、２００℃以上の
高温では用いられない。また、先に述べたスピンバルブ
膜は、用いられる反強磁性膜の耐熱性が悪く、半導体ホ
ール素子と同様に高温の環境下で用いるのは困難であ
る。On the other hand, semiconductor Hall elements used in many magnetic sensors have poor heat resistance and cannot be used at high temperatures of 200 ° C. or higher. In addition, the spin valve film described above has poor heat resistance of the antiferromagnetic film used, and is difficult to use in a high-temperature environment like a semiconductor Hall element.
【０００７】本発明は、上記の事情を鑑みてなされたも
ので、ＧＭＲ薄膜を軟磁性薄膜と複合化することによ
り、磁界感度が高く、且つＭＲ比の大きな磁気抵抗素子
を提供すること、および２００℃以上の温度環境におい
ても、使用可能な薄膜磁気抵抗素子を提供することを目
的とする。The present invention has been made in view of the above circumstances, and provides a magnetoresistive element having high magnetic field sensitivity and a high MR ratio by combining a GMR thin film with a soft magnetic thin film, and An object of the present invention is to provide a thin-film magnetoresistive element that can be used even in a temperature environment of 200 ° C. or higher.
【０００８】[0008]
【課題を解決するための手段】本発明は、上記の事情を
鑑みて鋭意努力した結果である。高い透磁率を有する軟
磁性薄膜と耐熱性の良好なＧＭＲ薄膜を組み合わせるこ
とによって、磁界感度が高く、耐熱性の良好な薄膜磁気
抵抗素子を得ることができる。SUMMARY OF THE INVENTION The present invention is a result of intensive efforts in view of the above circumstances. By combining a soft magnetic thin film having high magnetic permeability and a GMR thin film having good heat resistance, a thin film magnetoresistive element having high magnetic field sensitivity and good heat resistance can be obtained.
【０００９】本発明の特徴とするところは次の通りであ
る。第１発明は、軟磁性薄膜と巨大磁気抵抗薄膜とによ
って構成され、巨大磁気抵抗薄膜の両側に軟磁性薄膜を
配置することにより、磁気抵抗効果の磁界感度を上げた
薄膜磁気抵抗素子において、巨大磁気抵抗薄膜の膜厚が
軟磁性薄膜の膜厚以下であることを特徴とする薄膜磁気
抵抗素子に関する。The features of the present invention are as follows. The first invention is a thin-film magnetoresistive element which is composed of a soft magnetic thin film and a giant magnetoresistive thin film, and has a soft magnetic thin film disposed on both sides of the giant magnetoresistive thin film to increase the magnetic field sensitivity of the magnetoresistance effect. The present invention relates to a thin film magnetoresistive element, wherein the thickness of the magnetoresistive thin film is equal to or less than the thickness of the soft magnetic thin film.
【００１０】第２発明は、巨大磁気抵抗薄膜の電気比抵
抗が、軟磁性薄膜の電気比抵抗の１００倍以上大きいこ
とを特徴とする請求項１に記載の薄膜磁気抵抗素子に関
する。The second invention relates to the thin film magnetoresistive element according to claim 1, wherein the electric resistivity of the giant magnetoresistive thin film is at least 100 times larger than that of the soft magnetic thin film.
【００１１】第３発明は、軟磁性薄膜を電極とし、磁気
抵抗変化の５割以上が巨大磁気抵抗薄膜によって生じる
ことを特徴とする請求項１または請求項２に記載の薄膜
磁気抵抗素子に関する。According to a third aspect of the present invention, there is provided the thin film magnetoresistive element according to the first or second aspect, wherein a soft magnetic thin film is used as an electrode, and at least 50% of the change in magnetoresistance is caused by the giant magnetoresistive thin film.
【００１２】第４発明は、軟磁性薄膜の磁気特性が、保
磁力Ｈｃ≦２０ｅ、透磁率μ≧５００であり、且つ軟磁
性薄膜の飽和磁束密度（Ｂｓ）と膜厚（ｔ）および軟磁
性薄膜のギャップ幅（ｄ）の関係が、Ｂｓ（Ｇ）×ｔ
（μｍ）≧ｄ（μｍ）×２００であることを特徴とする
請求項１ないし請求項３のいずれか１項に記載の薄膜磁
気抵抗素子に関する。According to a fourth aspect of the present invention, the soft magnetic thin film has a coercive force Hc ≦ 20e, a magnetic permeability μ ≧ 500, and a saturation magnetic flux density (Bs), a film thickness (t) and a soft magnetic thin film of the soft magnetic thin film. The relationship of the gap width (d) of the thin film is Bs (G) × t
4. The thin-film magnetoresistive element according to claim 1, wherein (μm) ≧ d (μm) × 200.
【００１３】第５発明は、軟磁性薄膜のギャップ幅を変
化させることにより、磁気抵抗の磁界感度を任意に制御
することを特徴とする請求項１ないし請求項４のいずれ
か１項に記載の薄膜磁気抵抗素子に関する。The fifth invention is characterized in that the magnetic field sensitivity of the magnetic resistance is arbitrarily controlled by changing the gap width of the soft magnetic thin film. The present invention relates to a thin film magnetoresistive element.
【００１４】第６発明は、磁気特性の異なる軟磁性薄膜
を用いることによって、磁気抵抗の磁界感度を任意に制
御できることを特徴とする請求項１ないし請求項５のい
ずれか１項に記載の薄膜磁気抵抗素子に関する。According to a sixth aspect of the present invention, there is provided the thin film according to any one of claims 1 to 5, wherein the magnetic field sensitivity of the magnetic resistance can be arbitrarily controlled by using soft magnetic thin films having different magnetic properties. The present invention relates to a magnetoresistive element.
【００１５】第７発明は、薄膜磁気抵抗素子の占める容
積が１ｍｍ３以下であることを特徴とする請求項１ない
し請求項６のいずれか１項に記載の薄膜磁気抵抗素子に
関する。According to a seventh aspect of the present invention, there is provided the thin film magnetoresistive element according to any one of claims 1 to 6, wherein the volume occupied by the thin film magnetoresistive element is 1 mm 3 or less.
【００１６】第８発明は、２００℃以上の温度において
用いることを特徴とする請求項１ないし請求項７のいず
れか１項に記載の薄膜磁気抵抗素子に関する。According to an eighth aspect of the present invention, there is provided the thin-film magnetoresistive element according to any one of claims 1 to 7, wherein the element is used at a temperature of 200 ° C. or more.
【００１７】第９発明は、請求項１ないし請求項８のい
ずれか１項に記載の薄膜磁気抵抗素子からなる磁気メモ
リーに関する。A ninth invention relates to a magnetic memory comprising the thin-film magnetoresistive element according to any one of the first to eighth aspects.
【００１８】第１０発明は、請求項１ないし請求項８の
いずれか１項に記載の薄膜磁気抵抗素子からなる磁気セ
ンサーに関する。[0018] A tenth invention relates to a magnetic sensor comprising the thin-film magnetoresistive element according to any one of claims 1 to 8.
【００１９】第１１発明は、請求項１ないし請求項８の
いずれか１項に記載の薄膜磁気抵抗素子からなる磁気ヘ
ッドに関する。An eleventh invention relates to a magnetic head comprising the thin-film magnetoresistive element according to any one of the first to eighth aspects.
【００２０】[0020]
【作用】本発明の薄膜磁気抵抗素子は、軟磁性薄膜とＧ
ＭＲ薄膜を組み合わせることにより、軟磁性薄膜の高い
透磁率によって、弱磁界で大きなＭＲ比を現す。また、
薄膜材料を用いているため、素子の容積を小さくするこ
とが可能であり、１ｍｍ３以下の小型化に対応できる。
さらに、耐熱性の良好なＧＭＲ薄膜を用いることによっ
て、２００℃以上の温度においても良好なＭＲ特性が維
持される。The thin film magnetoresistive element of the present invention comprises a soft magnetic thin film and G
By combining the MR thin films, a high MR ratio is exhibited at a weak magnetic field due to the high magnetic permeability of the soft magnetic thin film. Also,
Since a thin film material is used, the volume of the element can be reduced, and the device can be reduced in size to 1 mm 3 or less.
Furthermore, by using a GMR thin film having good heat resistance, good MR characteristics are maintained even at a temperature of 200 ° C. or more.
【００２１】上記のような効果を得るためには、以下の
ことを考慮しなければならない。一つは、軟磁性薄膜と
ＧＭＲ薄膜の膜厚である。ＧＭＲ薄膜の膜厚が軟磁性薄
膜の膜厚よりも厚い場合は、軟磁性薄膜からの磁束が分
散してしまい、ＧＭＲ薄膜に有効に磁束が作用しない。
そのため、弱磁界で大きな磁界感度は得られない。した
がって、ＧＭＲ薄膜の膜厚は、軟磁性薄膜の膜厚以下で
なければならない。In order to obtain the above effects, the following must be considered. One is the thickness of the soft magnetic thin film and the GMR thin film. When the thickness of the GMR thin film is larger than the thickness of the soft magnetic thin film, the magnetic flux from the soft magnetic thin film is dispersed, and the magnetic flux does not act on the GMR thin film effectively.
Therefore, large magnetic field sensitivity cannot be obtained with a weak magnetic field. Therefore, the thickness of the GMR thin film must be less than the thickness of the soft magnetic thin film.
【００２２】二つは、ＧＭＲ薄膜の電気比抵抗である。
ＭＲ素子の磁界検出は、その電圧変化の検出によって行
われる。したがって、ＧＭＲ薄膜の電気抵抗が大きい方
が出力も大きい。また、軟磁性薄膜の中には、異方的磁
気抵抗（ＡＭＲ）を示すものがあるが、本発明の薄膜磁
気抵抗素子においてＡＭＲを示す軟磁性薄膜を組み込ん
だ場合、ＧＭＲ薄膜の電気比抵抗が軟磁性薄膜の電気比
抵抗よりも１００倍以上大きい場合は、ＡＭＲによる抵
抗変化は、ＧＭＲの抵抗変化に比べて非常に少ない。し
たがって、薄膜磁気抵抗素子の構造を簡略化するため
に、軟磁性膜を電極として利用しても、薄膜磁気抵抗素
子の電圧変化による出力の５割以上がＧＭＲ薄膜によっ
て生じる。The second is the electrical resistivity of the GMR thin film.
The magnetic field of the MR element is detected by detecting a change in the voltage. Therefore, the higher the electrical resistance of the GMR thin film, the higher the output. Some of the soft magnetic thin films exhibit anisotropic magnetoresistance (AMR). When a soft magnetic thin film exhibiting AMR is incorporated in the thin-film magnetoresistive element of the present invention, the electrical resistivity of the GMR thin film is reduced. Is larger than the electric resistivity of the soft magnetic thin film by 100 times or more, the change in resistance due to AMR is much smaller than the change in resistance due to GMR. Therefore, even if a soft magnetic film is used as an electrode to simplify the structure of the thin film magnetoresistive element, more than 50% of the output due to the voltage change of the thin film magnetoresistive element is generated by the GMR thin film.
【００２３】三つは、軟磁性薄膜の磁気特性とその形状
である。軟磁性膜の保磁力が２０ｅよりも大きく、透磁
率が５００より小さい場合は、弱磁界で十分に磁化しな
いため、良好なＭＲの磁界感度は得られない。また、軟
磁性薄膜の飽和磁束密度と形状が、Ｂｓ（Ｇ）×ｔ（μ
ｍ）≧ｄ（μｍ）×２００の条件を満たさない場合は、
ギャップのＧＭＲ薄膜に有効に磁束が作用せず、良好な
ＭＲ特性は得られない。The third is the magnetic properties and the shape of the soft magnetic thin film. When the coercive force of the soft magnetic film is larger than 20e and the magnetic permeability is smaller than 500, the magnetization is not sufficiently performed with a weak magnetic field, so that good magnetic field sensitivity of MR cannot be obtained. The saturation magnetic flux density and the shape of the soft magnetic thin film are Bs (G) × t (μ
m) ≧ d (μm) × 200 when the condition is not satisfied,
Magnetic flux does not effectively act on the GMR thin film in the gap, and good MR characteristics cannot be obtained.
【００２４】一方、ＭＲセンサーは、種々多様な磁界検
出に用いられている。種々な磁界検出のニーズに答える
ため、容易に磁界感度が制御できることが望ましい。本
発明の薄膜磁気抵抗素子は、軟磁性薄膜のギャップの幅
を変化させるか、もしくは磁気特性の異なる軟磁性薄膜
を用いることによって、磁気抵抗の磁界感度を任意に制
御できる。On the other hand, the MR sensor is used for detecting various magnetic fields. In order to meet various needs for magnetic field detection, it is desirable that magnetic field sensitivity can be easily controlled. In the thin film magnetoresistive element of the present invention, the magnetic field sensitivity of the magnetoresistance can be arbitrarily controlled by changing the width of the gap of the soft magnetic thin film or by using soft magnetic thin films having different magnetic properties.
【００２５】[0025]
【実施例】以下図面を参照して、本発明の実施例を詳細
に説明する。 〔実施例１〕薄膜磁気抵抗素子の作製 軟磁性薄膜としてパーマロイ（Ｆｅ６５Ｎｉ３５）薄膜
を用い、ＧＭＲ薄膜にＣｏ３８．６Ｙ４１．０Ｏ
４７．４ナノグラニュラー薄膜を用いて、薄膜磁気抵抗
素子を作製した。作製した薄膜磁気抵抗素子の概略を図
１に示す。パーマロイ薄膜およびＣｏ３８．６Ｙ
４１．０Ｏ４７．４ナノグラニュラー薄膜の作製にはＲ
Ｆスパッタ装置を用いた。Embodiments of the present invention will be described below in detail with reference to the drawings. Example 1 using a permalloy (Fe 65 Ni 35) thin film as manufactured soft magnetic thin film of the thin film magnetoresistive element, Co 38.6 Y 41.0 O to the GMR film
Using a 47.4 nanogranular thin film, a thin film magnetoresistive element was produced. FIG. 1 shows an outline of the manufactured thin film magnetoresistive element. Permalloy thin film and Co 38.6 Y
For the preparation of 41.0 O 47.4 nanogranular thin film, R
An F sputtering apparatus was used.
【００２６】パーマロイ（Ｆｅ６５Ｎｉ３５）薄膜は、
Ｆｅ６５Ｎｉ３５合金ターゲットをスパッタして作製し
た。膜厚は約２μｍである。さらに、得られた薄膜にイ
オンビームエッチング装置を用いて、幅約５μｍの隙間
を作製した。そして、隙間の部分を中心に隙間より広い
範囲を残して軟磁性薄膜をマスクし、その部分に、純Ｃ
ｏ円板上にＹ２Ｏ３チップを配置した複合ターゲットを
スパッタすることにより、Ｃｏ３８．６Ｙ４１．０Ｏ
４７．４ナノグラニュラーＧＭＲ薄膜を作製した。膜厚
は、パーマロイ（Ｆｅ６５Ｎｉ３５）の膜厚以下の約１
μｍである。これによって、図１に示したようなＣｏ
３８．６Ｙ４１．０Ｏ４７．４ＧＭＲ薄膜の両側に、パ
ーマロイ（Ｆｅ６５Ｎｉ３５）薄膜を配置した薄膜磁気
抵抗素子が得られた。図２には、上記の薄膜磁気抵抗素
子の磁界に対するＭＲ変化を示す。ＭＲ比は極めて弱い
磁界において急激に変化し、その値は１０ｅの弱磁界に
おいて約６％であり、高い磁界感度を示している。The permalloy (Fe 65 Ni 35 ) thin film is
It was produced by sputtering an Fe 65 Ni 35 alloy target. The thickness is about 2 μm. Further, a gap having a width of about 5 μm was formed on the obtained thin film by using an ion beam etching apparatus. Then, the soft magnetic thin film is masked leaving a wider area than the gap centering on the gap, and pure C
o By sputtering a composite target having a Y 2 O 3 chip disposed on a disc, Co 38.6 Y 41.0 O
A 47.4 nanogranular GMR thin film was prepared. The film thickness is about 1 or less of the thickness of permalloy (Fe 65 Ni 35 ).
μm. As a result, Co as shown in FIG.
A thin-film magnetoresistive element in which a permalloy (Fe 65 Ni 35 ) thin film was disposed on both sides of the 38.6 Y 41.0 O 47.4 GMR thin film was obtained. FIG. 2 shows an MR change with respect to a magnetic field of the thin film magnetoresistive element. The MR ratio changes abruptly in an extremely weak magnetic field, and its value is about 6% in a weak magnetic field of 10e, indicating high magnetic field sensitivity.
【００２７】図１に示すように、パーマロイ（Ｆｅ６５
Ｎｉ３５）薄膜は電極を兼ね、ＧＭＲ薄膜に電流を導入
している。ところが、図３に示すようにＭＲ比の飽和値
は、測定方向に依存せず、パーマロイ膜のＡＭＲはほと
んど観察されない。また、ＧＭＲ薄膜はギャップ幅に比
べて、広い範囲でパーマロイ膜を覆っているが、磁気素
子に流れる電流の大部分は、ギャップの最も狭い部分を
流れる。これらのことは、Ｃｏ３８．６Ｙ４１．０Ｏ
４７．４膜の電気比抵抗（１４×１０４μΩｃｍ）が、
パーマロイの電気比抵抗（５５μΩｃｍ）に比べて１０
０倍以上大きいためである。電気比抵抗の大幅に異なる
軟磁性薄膜とＧＭＲ薄膜を組み合わせることによって、
磁束導入部分と電極を兼用できること、またＧＭＲ薄膜
作製の際のマスク合わせがラフで良いことなど、磁気素
子の構造および作製工程が簡略化される。As shown in FIG. 1, permalloy (Fe 65
The Ni 35 ) thin film also serves as an electrode, and introduces current into the GMR thin film. However, as shown in FIG. 3, the saturation value of the MR ratio does not depend on the measurement direction, and the AMR of the permalloy film is hardly observed. Further, the GMR thin film covers the permalloy film in a wider range than the gap width, but most of the current flowing through the magnetic element flows through the narrowest portion of the gap. These facts indicate that Co 38.6 Y 41.0 O
The electrical resistivity of the 47.4 film (14 × 10 4 μΩcm)
10 compared to the electrical resistivity of Permalloy (55μΩcm)
This is because it is larger than 0 times. By combining a soft magnetic thin film and a GMR thin film with greatly different electrical resistivity,
The structure and manufacturing process of the magnetic element are simplified, for example, the magnetic flux introduction part can be used as an electrode, and the mask alignment at the time of manufacturing the GMR thin film can be rough.
【００２８】〔実施例２〕ギャップ幅を変化させた薄膜
磁気抵抗素子のＭＲ特性 図４に、軟磁性薄膜のギャップ幅を変化させた場合のＭ
Ｒ曲線を示す。ギャップ幅が広くなると、軟磁性薄膜か
らの漏れ磁束が分散するため、ＧＭＲ薄膜に作用する磁
束が少なくなる。これを利用してＭＲの磁界感度が制御
でき、図４に示すように、ギャップ幅を変化させること
によって、ＭＲの磁界感度が任意に制御できる。[Example 2] MR characteristics of a thin film magnetoresistive element having a changed gap width FIG. 4 shows the M characteristics when the gap width of a soft magnetic thin film is changed.
The R curve is shown. When the gap width is increased, the magnetic flux acting on the GMR thin film decreases because the magnetic flux leaking from the soft magnetic thin film is dispersed. By utilizing this, the magnetic field sensitivity of the MR can be controlled, and as shown in FIG. 4, the magnetic field sensitivity of the MR can be arbitrarily controlled by changing the gap width.
【００２９】〔実施例３〕軟磁性薄膜の磁気特性を変化
させた薄膜磁気抵抗素子のＭＲ特性 図５に、軟磁性薄膜の透磁率を変化させた場合のＭＲ曲
線を示す。軟磁性薄膜の透磁率は、熱処理条件を変えて
変化させた。図５に示すように、軟磁性薄膜の磁気特性
を変化させることによって、ＭＲの磁界感度が任意に制
御できる。[Embodiment 3] MR characteristics of a thin film magnetoresistive element in which the magnetic characteristics of a soft magnetic thin film are changed FIG. 5 shows MR curves when the magnetic permeability of the soft magnetic thin film is changed. The magnetic permeability of the soft magnetic thin film was changed by changing the heat treatment conditions. As shown in FIG. 5, the magnetic field sensitivity of the MR can be arbitrarily controlled by changing the magnetic characteristics of the soft magnetic thin film.
【００３０】〔実施例４〕薄膜磁気抵抗素子の耐熱性 実施例１に示した薄膜磁気抵抗素子のＭＲ比を、種々の
温度環境下で測定した結果を図６に示す。ＭＲ比は３５
０℃まで変化せず、本発明の薄膜磁気抵抗素子は良好な
耐熱性を有することがわかる。Example 4 Heat Resistance of Thin Film Magnetoresistance Element FIG. 6 shows the results of measuring the MR ratio of the thin film magnetoresistance element shown in Example 1 under various temperature environments. MR ratio is 35
It does not change up to 0 ° C., indicating that the thin film magnetoresistive element of the present invention has good heat resistance.
【００３１】上記の通り、本発明の薄膜磁気抵抗素子
は、ＭＲ比の磁界感度および耐熱性が優れているので、
磁気センサ、磁気ヘッドまたは磁気メモリーなどにも好
適である。As described above, the thin film magnetoresistive element of the present invention is excellent in magnetic field sensitivity of MR ratio and heat resistance.
It is also suitable for a magnetic sensor, a magnetic head or a magnetic memory.
【００３２】[0032]
【発明の効果】本発明の薄膜磁気抵抗素子は、軟磁性薄
膜とＧＭＲ薄膜とから構成され、弱磁界において非常に
大きなＭＲ比を有し、磁界感度が極めて優れている。ま
た、磁界感度を任意に制御できるので、種々の磁界検出
の用途に応用でき、さらに耐熱性も良好なので、その工
業的意義は大きく、磁気ヘッド、磁気センサおよび磁気
メモリーなどにも好適である。The thin-film magnetoresistive element of the present invention comprises a soft magnetic thin film and a GMR thin film, has a very large MR ratio in a weak magnetic field, and has extremely excellent magnetic field sensitivity. In addition, since the magnetic field sensitivity can be controlled arbitrarily, it can be applied to various magnetic field detection applications and has good heat resistance, so that it has great industrial significance and is suitable for magnetic heads, magnetic sensors, magnetic memories, and the like.
【図１】図１は、本発明薄膜磁気抵抗素子の構造を示す
斜視図である。FIG. 1 is a perspective view showing the structure of a thin film magnetoresistive element according to the present invention.
【図２】図２は、本発明薄膜磁気抵抗素子の磁界とＭＲ
比の関係を示す特性図である。FIG. 2 is a graph showing the relationship between the magnetic field and MR of the thin film magnetoresistive element of the present invention.
FIG. 4 is a characteristic diagram showing a ratio relationship.
【図３】図３は、本発明薄膜磁気抵抗素子の測定方向を
変えた場合の磁界とＭＲ比の関係を示す特性図である。FIG. 3 is a characteristic diagram showing a relationship between a magnetic field and an MR ratio when the measurement direction of the thin film magnetoresistive element of the present invention is changed.
【図４】図４は、本発明薄膜磁気抵抗素子のギャップ幅
を変えた場合の磁界とＭＲ比の関係を示す特性図であ
る。FIG. 4 is a characteristic diagram showing a relationship between a magnetic field and an MR ratio when the gap width of the thin film magnetoresistive element of the present invention is changed.
【図５】図５は、本発明薄膜磁気抵抗素子の軟磁性薄膜
の透磁率を変化させた場合の磁界とＭＲ比の関係を示す
特性図である。FIG. 5 is a characteristic diagram showing a relationship between a magnetic field and an MR ratio when the magnetic permeability of the soft magnetic thin film of the thin film magnetoresistive element of the present invention is changed.
【図６】図６は、本発明薄膜磁気抵抗素子の測定温度と
１０ｅにおけるＭＲ比の関係を示す特性図である。FIG. 6 is a characteristic diagram showing the relationship between the measured temperature and the MR ratio at 10e of the thin film magnetoresistive element of the present invention.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 三谷 誠司 宮城県仙台市太白区八木山緑町７丁目41番 305号 (72)発明者 藤森 啓安 宮城県仙台市青葉区吉成２丁目20番３号 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Seiji Mitani 7-41 305, No. 305, Midoricho, Yagiyama-ku, Taishiro-ku, Sendai-city, Miyagi-ken
Claims (11)
て構成され、巨大磁気抵抗薄膜の両側に軟磁性薄膜を配
置することにより、磁気抵抗効果の磁界感度を上げた薄
膜磁気抵抗素子において、巨大磁気抵抗薄膜の膜厚が軟
磁性薄膜の膜厚以下であることを特徴とする薄膜磁気抵
抗素子。1. A thin-film magnetoresistive element comprising a soft magnetic thin film and a giant magnetoresistive thin film, and arranging soft magnetic thin films on both sides of the giant magnetoresistive thin film to increase the magnetic field sensitivity of a magnetoresistive effect. A thin film magnetoresistive element, wherein the thickness of the magnetoresistive thin film is equal to or less than the thickness of the soft magnetic thin film.
性薄膜の電気比抵抗の１００倍以上大きいことを特徴と
する請求項１に記載の薄膜磁気抵抗素子。2. The thin film magnetoresistive element according to claim 1, wherein the electric resistivity of the giant magnetoresistive thin film is at least 100 times larger than that of the soft magnetic thin film.
５割以上が巨大磁気抵抗薄膜によって生じることを特徴
とする請求項１または請求項２に記載の薄膜磁気抵抗素
子。3. The thin film magnetoresistive element according to claim 1, wherein the soft magnetic thin film is used as an electrode, and at least 50% of the change in magnetoresistance is caused by the giant magnetoresistive thin film.
２０ｅ、透磁率μ≧５００であり、且つ軟磁性薄膜の飽
和磁束密度（Ｂｓ）と膜厚（ｔ）および軟磁性薄膜のギ
ャップ幅（ｄ）の関係が、Ｂｓ（Ｇ）×ｔ（μｍ）≧ｄ
（μｍ）×２００であることを特徴とする請求項１ない
し請求項３のいずれか１項に記載の薄膜磁気抵抗素子。4. The magnetic property of the soft magnetic thin film is such that the coercive force Hc ≦
20e, the magnetic permeability μ ≧ 500, and the relationship between the saturation magnetic flux density (Bs) of the soft magnetic thin film, the film thickness (t), and the gap width (d) of the soft magnetic thin film is Bs (G) × t (μm). ≧ d
The thin film magnetoresistive element according to any one of claims 1 to 3, wherein (μm) × 200.
とにより、磁気抵抗の磁界感度を任意に制御することを
特徴とする請求項１ないし請求項４のいずれか１項に記
載の薄膜磁気抵抗素子。5. The thin film magnetoresistive device according to claim 1, wherein the magnetic field sensitivity of the magnetoresistive device is arbitrarily controlled by changing a gap width of the soft magnetic thin film. element.
とによって、磁気抵抗の磁界感度を任意に制御できるこ
とを特徴とする請求項１ないし請求項５のいずれか１項
に記載の薄膜磁気抵抗素子。6. The thin-film magnetoresistive element according to claim 1, wherein the magnetic field sensitivity of the magnetoresistance can be arbitrarily controlled by using soft magnetic thin films having different magnetic properties. .
３以下であることを特徴とする請求項１ないし請求項６
のいずれか１項に記載の薄膜磁気抵抗素子。7. The volume occupied by the thin-film magnetoresistive element is 1 mm.
7. The number is 3 or less.
The thin film magnetoresistive element according to any one of the above items.
を特徴とする請求項１ないし請求項７のいずれか１項に
記載の薄膜磁気抵抗素子。8. The thin film magnetoresistive element according to claim 1, wherein the element is used at a temperature of 200 ° C. or higher.
に記載の薄膜磁気抵抗素子からなる磁気メモリー。9. A magnetic memory comprising the thin-film magnetoresistive element according to claim 1. Description:
に記載の薄膜磁気抵抗素子からなる磁気センサー。10. A magnetic sensor comprising the thin-film magnetoresistive element according to any one of claims 1 to 8.
に記載の薄膜磁気抵抗素子からなる磁気ヘッド。11. A magnetic head comprising the thin-film magnetoresistive element according to any one of claims 1 to 8.
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| JP11130198A JP3466470B2 (en) | 1998-03-18 | 1998-03-18 | Thin film magnetoresistive element |
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|---|---|---|---|
| JP11130198A JP3466470B2 (en) | 1998-03-18 | 1998-03-18 | Thin film magnetoresistive element |
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