JP5032009B2 - Magnetic sensor, magnetic head, and magnetic recording / reproducing apparatus - Google Patents

Magnetic sensor, magnetic head, and magnetic recording / reproducing apparatus Download PDF

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JP5032009B2
JP5032009B2 JP2005225715A JP2005225715A JP5032009B2 JP 5032009 B2 JP5032009 B2 JP 5032009B2 JP 2005225715 A JP2005225715 A JP 2005225715A JP 2005225715 A JP2005225715 A JP 2005225715A JP 5032009 B2 JP5032009 B2 JP 5032009B2
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藤 利 江 佐
島 公 一 水
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Description

本発明は磁気センサ、磁気ヘッド、および磁気記録再生装置に関する。   The present invention relates to a magnetic sensor, a magnetic head, and a magnetic recording / reproducing apparatus.

巨大磁気抵抗効果（ＧＭＲ効果）を利用したＧＭＲヘッドの登場以来、磁気記録の記録密度は、年率１００％で向上している。ＧＭＲ素子は、強磁性層／非磁性層／強磁性層のサンドイッチ構造の積層膜からなる。ＧＭＲ素子は、一方の強磁性層に交換バイアスを及ぼして磁化を固着し、他方の強磁性層の磁化方向を外部磁界により変化させ、２つの強磁性層の磁化方向の相対角度の変化を抵抗値の変化として検出する、いわゆるスピンバルブ膜の磁気抵抗効果を利用した素子である。スピンバルブ膜の膜面に電流を流し、抵抗変化を検出するＣＩＰ(Current In Plane)−ＧＭＲ素子と、スピンバルブ膜の膜面に垂直に電
流を流し抵抗変化を検出するＣＰＰ(Current Perpendicular to Plane)−ＧＭＲ素子が開発されている。その磁気抵抗比（ＭＲ比）はＣＩＰ−ＧＭＲ素子、ＣＰＰ−ＧＭＲ素子とも数％程度であり、２００Ｇｂｉｔ／ｉｎｃｈ２程度の記録密度まで対応可能であろうと考えられている。 Since the advent of GMR heads using the giant magnetoresistive effect (GMR effect), the recording density of magnetic recording has improved at an annual rate of 100%. The GMR element is composed of a laminated film having a sandwich structure of ferromagnetic layer / nonmagnetic layer / ferromagnetic layer. The GMR element applies an exchange bias to one of the ferromagnetic layers to fix the magnetization, changes the magnetization direction of the other ferromagnetic layer by an external magnetic field, and resists a change in the relative angle between the magnetization directions of the two ferromagnetic layers. It is an element that utilizes the magnetoresistive effect of a so-called spin valve film that is detected as a change in value. A CIP (Current In Plane) -GMR element that detects a resistance change by passing a current through the film surface of the spin valve film, and a CPP (Current Perpendicular to Plane) that detects a resistance change by flowing a current perpendicular to the film surface of the spin valve film ) -GMR elements have been developed. The magnetoresistance ratio (MR ratio) of both the CIP-GMR element and the CPP-GMR element is about several percent, and it is considered that a recording density of about 200 Gbit / inch 2 can be handled.

より高密度な磁気記録に対応するため、トンネル磁気抵抗効果（ＴＭＲ効果）を利用したＴＭＲ素子の開発が進められている。ＴＭＲ素子は強磁性層／絶縁体／強磁性層の積層膜からなり、強磁性層間に電圧を印加しトンネル電流を流す。ＴＭＲ素子は、トンネル電流の大きさが上下の強磁性層の磁化の向きによって変化することを利用し、磁化の相対的角度の変化をトンネル抵抗値の変化として検出する素子である。ＭＲ比は最大で５０％程度の素子が得られている。ＴＭＲ素子は、ＧＭＲ素子よりもＭＲ比が大きいため、信号電圧も大きくなる。   In order to cope with higher-density magnetic recording, development of a TMR element using the tunnel magnetoresistance effect (TMR effect) has been advanced. The TMR element is composed of a laminated film of a ferromagnetic layer / insulator / ferromagnetic layer, and applies a voltage between the ferromagnetic layers to cause a tunnel current to flow. The TMR element is an element that detects a change in the relative angle of magnetization as a change in tunnel resistance value by utilizing the fact that the magnitude of the tunnel current changes depending on the magnetization directions of the upper and lower ferromagnetic layers. An element having an MR ratio of about 50% at maximum is obtained. Since the TMR element has a larger MR ratio than the GMR element, the signal voltage is also increased.

しかしながら、純粋な信号成分だけでなく、ショットノイズによる雑音成分も大きくなり、Ｓ／Ｎ比（信号対雑音比）がよくならないという問題を抱えている。ショットノイズは、電子がトンネル障壁を不規則に通過することによって発生する電流の揺らぎに起因しており、トンネル抵抗値の平方根に比例して増大する。従ってショットノイズを抑え、必要な信号電圧を得るには、トンネル絶縁層を薄くし、トンネル抵抗を低抵抗化する必要がある。   However, not only a pure signal component but also a noise component due to shot noise is increased, and the S / N ratio (signal-to-noise ratio) is not improved. Shot noise is caused by fluctuations in current generated by electrons passing irregularly through the tunnel barrier, and increases in proportion to the square root of the tunnel resistance value. Therefore, in order to suppress shot noise and obtain a necessary signal voltage, it is necessary to make the tunnel insulating layer thin and to reduce the tunnel resistance.

記録密度が高密度化するほど素子サイズは記録ビットと同程度のサイズに小さくする必要があるため、高密度になるほどトンネル絶縁層の接合抵抗を小さく、つまり、絶縁層を薄くする必要がある。３００Ｇｂｉｔ／ｉｎｃｈ２の記録密度では１Ω・ｃｍ２以下の接合抵抗が必要とされ、Ａｌ−Ｏ（アルミニウム酸化膜）トンネル絶縁層の膜厚に換算して原子２層分の厚さのトンネル絶縁層を形成しなければならない。トンネル絶縁層を薄くするほど上下電極間の短絡が生じやすくＭＲ比の低下を招くため、素子の作製は飛躍的に困難になっていく。以上の理由によってＴＭＲ素子の限界は３００Ｇｂｉｔ／ｉｎｃｈ２であろうと見積もられている。 As the recording density increases, the element size needs to be reduced to the same size as the recording bit. Therefore, the higher the density, the smaller the junction resistance of the tunnel insulating layer, that is, the thinner the insulating layer. With a recording density of 300 Gbit / inch 2 , a junction resistance of 1 Ω · cm 2 or less is required, and the tunnel insulating layer has a thickness of two atoms in terms of the thickness of the Al—O (aluminum oxide film) tunnel insulating layer. Must be formed. As the tunnel insulating layer is made thinner, a short circuit between the upper and lower electrodes is more likely to occur, and the MR ratio is lowered. For the above reasons, it is estimated that the limit of the TMR element will be 300 Gbit / inch 2 .

上に述べた素子はいずれも広い意味での磁気抵抗効果を利用しているが、これらの素子に共通した磁気的白色雑音（ホワイトノイズ）の問題が近年急浮上している。この雑音は上に述べたショットノイズなどの電気的ノイズとは異なり、磁化の熱ゆらぎに起因して生じるため素子の微細化に伴いより支配的となり２００Ｇｂｐｓｉ〜３００Ｇｂｐｓｉ対応の素子では電気的雑音を凌駕すると考えられている。磁気的白色雑音を回避し、磁気記録の記録密度をさらに高めるためには従来の磁気抵抗効果とは異なった原理により動作する微小磁気センサが必要となるが、そのような磁気センサとして共鳴磁気抵抗効果素子の開発が進めら
れている（例えば、非特許文献１参照）。
R. Sato, et. al. J. Magn. Magn. Mat. vol.279, p.36 (2004) All of the above-described elements utilize the magnetoresistive effect in a broad sense, but the problem of magnetic white noise (white noise) common to these elements has recently emerged rapidly. Unlike electrical noise such as shot noise described above, this noise is caused by thermal fluctuations in magnetization, so that it becomes more dominant as devices become smaller, and exceeds 200 Gbpsi to 300 Gbpsi for electrical noise. It is considered to be. In order to avoid magnetic white noise and further increase the recording density of magnetic recording, a micromagnetic sensor that operates on a principle different from the conventional magnetoresistive effect is required. Development of effect elements is underway (for example, see Non-Patent Document 1).
R. Sato, et. Al. J. Magn. Magn. Mat. Vol. 279, p. 36 (2004)

従来の共鳴磁気抵抗効果素子は、膜厚が１ｎｍ以下の非磁性層を磁化の方向が垂直である強磁性層で挟んだ構造の、磁性体として欠陥の少ない人工反強磁性体を用いることにより実効高周波磁場の強度を増大させ特性向上を図ってきた。しかし、この人工反強磁性体は、高度の成膜技術を必要とするため実用化には多くの困難を抱えている。このため、現在十分な特性が得られていない。   A conventional resonant magnetoresistive effect element uses an artificial antiferromagnet having a small number of defects as a magnetic body having a structure in which a nonmagnetic layer having a thickness of 1 nm or less is sandwiched between ferromagnetic layers having a perpendicular magnetization direction. We have attempted to improve the characteristics by increasing the strength of the effective high-frequency magnetic field. However, since this artificial antiferromagnetic material requires advanced film formation technology, it has many difficulties in practical use. For this reason, sufficient characteristics are not currently obtained.

上に述べたように、高密度磁気記録において大きな問題となっている磁気的白色雑音の問題を解決するために共鳴磁気抵抗効果を用いた新しい磁気センサの開発が進められているが、現在十分な特性が得られていない。   As described above, a new magnetic sensor using the resonant magnetoresistive effect is being developed to solve the magnetic white noise problem, which is a major problem in high-density magnetic recording. The characteristic is not acquired.

本発明は、上記事情を考慮してなされたものであって、磁気的白色雑音を可及的に抑制することのできる磁気センサ、磁気ヘッド、磁気記録再生装置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 an object thereof is to provide a magnetic sensor, a magnetic head, and a magnetic recording / reproducing apparatus that can suppress magnetic white noise as much as possible.

本発明の第１の態様による共鳴磁気抵抗効果素子は、磁化の向きが膜面に実質的に平行な第１磁性層と、磁化の向きが膜面に実質的に垂直な第２磁性層と、前記第１および第２磁性層の間に設けられた第１非磁性層とを備えていることを特徴とする。   The resonant magnetoresistive element according to the first aspect of the present invention includes a first magnetic layer whose magnetization direction is substantially parallel to the film surface, and a second magnetic layer whose magnetization direction is substantially perpendicular to the film surface. And a first nonmagnetic layer provided between the first and second magnetic layers.

また、本発明の第２の態様による共鳴磁気抵抗効果素子は、磁化の向きが膜面に実質的に平行な第１および第２磁性層と、前記第１および第２磁性層間に設けられ、磁化の向きが膜面に実質的に垂直な第３磁性層および非磁性層が複数個積層された積層膜とを備えていることを特徴とする。
また、本発明の第３の態様による磁気ヘッドは、上記共鳴磁気抵抗効果素子を再生素子として搭載したことを特徴とする。
また、本発明の第４の態様による磁気記録再生装置は、上記磁気ヘッドを備えていることを特徴とする。 The resonant magnetoresistive effect element according to the second aspect of the present invention is provided between the first and second magnetic layers whose magnetization directions are substantially parallel to the film surface, and the first and second magnetic layers, A third magnetic layer having a magnetization direction substantially perpendicular to the film surface; and a laminated film in which a plurality of nonmagnetic layers are laminated.
A magnetic head according to a third aspect of the present invention is characterized in that the resonant magnetoresistive element is mounted as a reproducing element.
A magnetic recording / reproducing apparatus according to the fourth aspect of the present invention includes the above magnetic head.

本発明によれば、磁気的白色雑音を可及的に抑制することができる。   According to the present invention, magnetic white noise can be suppressed as much as possible.

まず、本発明の実施形態を説明する前に、磁性発信素子の一種である共鳴磁気抵抗効果素子について、説明する。共鳴磁気抵抗効果素子は軟磁性体において不可避な磁化の熱ゆらぎを積極的に利用するもので、強磁性体の磁化の熱ゆらぎによって生じる伝導電子のスピンゆらぎを磁性体に注入することを特徴とするものである。注入された伝導電子のスピンゆらぎはｓｄ交換相互作用などの相互作用を介して磁性体に実効高周波磁場として作用し、磁性体に磁気共鳴を誘起する。外部磁場が変化し強磁性体磁化のゆらぎが変化すると磁性体に誘起される磁気共鳴の強度が変化するが、この変化は磁性体の実効的電気抵抗の変化として検知される。このような原理により約１０エルステッドの外部磁場の変化に対して数１０％〜数１００％の素子抵抗変化が得られ、微小高感度磁気センサとして機能する。   First, before describing an embodiment of the present invention, a resonant magnetoresistive element, which is a kind of magnetic transmission element, will be described. Resonant magnetoresistive elements actively utilize thermal fluctuations of magnetization that are unavoidable in soft magnetic materials, and are characterized by injecting spin fluctuations of conduction electrons caused by thermal fluctuations of magnetization of ferromagnetic materials into magnetic materials. To do. The spin fluctuation of the injected conduction electrons acts as an effective high-frequency magnetic field on the magnetic material through an interaction such as sd exchange interaction, and induces magnetic resonance in the magnetic material. When the external magnetic field changes and the fluctuation of the ferromagnetic magnetization changes, the intensity of magnetic resonance induced in the magnetic substance changes. This change is detected as a change in the effective electrical resistance of the magnetic substance. By such a principle, an element resistance change of several 10% to several 100% is obtained with respect to an external magnetic field change of about 10 Oersteds, and functions as a minute high sensitivity magnetic sensor.

以下、本発明の実施形態について、図面を参照しつつ詳細に説明する。尚、以後の説明では、共通の構成に同一の符号を付すものとし、重複する説明は省略する。また、各図は模式図であり、その形状や寸法、比などは実際の装置と異なる個所も含んでいるが、実際に素子等を製造する際には、以下の説明と公知の技術の参酌により適宜変更することができる。   Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same reference numerals are assigned to the common components, and duplicate descriptions are omitted. Each figure is a schematic diagram, and its shape, dimensions, ratio, etc. include parts that are different from the actual device. However, when actually manufacturing elements etc., the following explanation and consideration of known techniques are considered. Can be changed as appropriate.

（第１実施形態）
本発明の第１実施形態による共鳴磁気抵抗効果素子の構成を図１に示す。図１は本実施形態による共鳴磁気抵抗効果素子の構成を示す断面図である。本実施形態による共鳴磁気抵抗効果素子は、基板１上に設けられ、磁気シールドを兼ねた下部電極３と、この下部電極３上に設けられ磁化の向きが膜面に実質的に垂直な強磁性層５と、強磁性層５上に設けられた非磁性層７と、この非磁性層７上に設けられ磁化の向きが膜面に実質的に平行な強磁性層９と、強磁性層９上に設けられ磁気シールドを兼ねた上部電極１１とを備えている。強磁性層５、非磁性層７、および強磁性９は平面形状が同一の積層膜４となっている。強磁性層５は磁化の向きが膜面に実質的に垂直すなわち磁化容易軸が膜面に垂直な方向であり、強磁性層９は磁化の向きが膜面に実質的に平行な方向すなわち磁化容易軸が膜面に平行な方向である。なお、本実施形態においては、「実質的に垂直」とは、完全に垂直な状態から±１５度の傾斜を含んでおり、「実質的に平行」とは、完全に平行な状態から±１５度の傾斜を含んでいる。 (First embodiment)
The configuration of the resonant magnetoresistive element according to the first embodiment of the present invention is shown in FIG. FIG. 1 is a cross-sectional view showing the configuration of the resonant magnetoresistive element according to the present embodiment. The resonant magnetoresistive element according to the present embodiment is provided on the substrate 1 and has a lower electrode 3 that also serves as a magnetic shield, and a ferromagnetic that is provided on the lower electrode 3 and whose magnetization direction is substantially perpendicular to the film surface. A layer 5, a nonmagnetic layer 7 provided on the ferromagnetic layer 5, a ferromagnetic layer 9 provided on the nonmagnetic layer 7 and having a magnetization direction substantially parallel to the film surface, and a ferromagnetic layer 9 And an upper electrode 11 also serving as a magnetic shield. The ferromagnetic layer 5, the nonmagnetic layer 7, and the ferromagnet 9 are the laminated films 4 having the same planar shape. The ferromagnetic layer 5 has a magnetization direction substantially perpendicular to the film surface, that is, a direction in which the easy axis is perpendicular to the film surface, and the ferromagnetic layer 9 has a magnetization direction substantially parallel to the film surface, that is, magnetization. The easy axis is a direction parallel to the film surface. In this embodiment, “substantially vertical” includes an inclination of ± 15 degrees from a completely vertical state, and “substantially parallel” means ± 15 from a completely parallel state. Includes a degree tilt.

下部電極３と上部電極１１は配線も兼ねているため、図１の紙面横方向に伸びており、その端部において素子に流す電流を制御する電流供給回路や読出し（センス）回路などと接続される。なお、下部電極３と上部電極１１は磁気シールドと配線も兼ねているが、磁気シールドや配線を下部電極や上部電極と別に設けることも可能である。この場合にも、磁気シールドや配線は、下部電極３、上部電極１１および強磁性層９の膜面と平行な面内（図１の断面では紙面左右方向に伸びる平面内）に形成することができる。   Since the lower electrode 3 and the upper electrode 11 also serve as wiring, the lower electrode 3 and the upper electrode 11 extend in the horizontal direction in FIG. 1, and are connected to a current supply circuit, a reading (sense) circuit, or the like that controls the current flowing through the element at the end. The The lower electrode 3 and the upper electrode 11 also serve as a magnetic shield and a wiring. However, the magnetic shield and the wiring can be provided separately from the lower electrode and the upper electrode. Also in this case, the magnetic shield and the wiring may be formed in a plane parallel to the film surfaces of the lower electrode 3, the upper electrode 11, and the ferromagnetic layer 9 (in the plane extending in the left-right direction on the paper surface in the cross section of FIG. 1). it can.

本実施形態の共鳴磁気抵抗効果素子は、強磁性体において不可避な磁化の熱ゆらぎを積極的に利用する。つまり、強磁性層９の磁化の熱ゆらぎに起因する伝導電子のスピンゆらぎを、非磁性層７を介して強磁性層５に注入するものである。注入された伝導電子のスピンゆらぎは、ｓｄ交換相互作用などを介して強磁性層５にスピントルクを及ぼすため実効高周波磁場として作用し、強磁性層５に閾値電流Ｉｔｈ以上で磁気共鳴を誘起する。外部磁場が変化して強磁性層９の磁化のゆらぎスペクトルが変化すると、強磁性層５に誘起される磁気共鳴の強度が変化するが、この強度変化は共鳴磁気抵抗効果素子の実効的電気抵抗の変化として検知される。このような原理により、数１０エルステッド（Ｏｅ）の外部磁場の変化に対して数１００％〜数１０００％の素子抵抗変化が得られる。 The resonant magnetoresistive element according to the present embodiment positively utilizes thermal fluctuations of magnetization that are unavoidable in ferromagnetic materials. That is, the spin fluctuation of conduction electrons caused by the thermal fluctuation of the magnetization of the ferromagnetic layer 9 is injected into the ferromagnetic layer 5 through the nonmagnetic layer 7. Spin fluctuation of the injected conduction electrons, induce magnetic resonance, such as over a sd exchange interaction acts as an effective high frequency magnetic field to exert a spin torque to the ferromagnetic layer 5, a ferromagnetic layer 5 in the threshold current I th or To do. When the external magnetic field changes and the fluctuation spectrum of the magnetization of the ferromagnetic layer 9 changes, the intensity of magnetic resonance induced in the ferromagnetic layer 5 changes. This intensity change depends on the effective electrical resistance of the resonant magnetoresistive element. Is detected as a change. According to such a principle, a device resistance change of several hundreds to several thousand% can be obtained with respect to a change of an external magnetic field of several tens of Oersted (Oe).

このように本実施形態の共鳴磁気抵抗効果素子は微小高感度磁気センサとして機能する。本実施形態の共鳴磁気抵抗効果素子は後に詳述するように強磁性層９および強磁性層５の磁化の熱ゆらぎを利用するため、素子の接合面積（強磁性層５、非磁性層７、強磁性層９間の接合面積）が減少しても、感度およびＳＮ比がほとんど低減しないという特徴を有する。よって、磁気情報再生用磁気ヘッドへ応用した場合には、記録密度が数１００Ｇｂｐｓｉから１Ｔｂｐｓｉを超える超高密度記録への対応が可能である。   Thus, the resonant magnetoresistive effect element of this embodiment functions as a minute high-sensitivity magnetic sensor. As will be described in detail later, the resonant magnetoresistive element of the present embodiment uses thermal fluctuations in magnetization of the ferromagnetic layer 9 and the ferromagnetic layer 5, so that the junction area (ferromagnetic layer 5, nonmagnetic layer 7, Even if the junction area between the ferromagnetic layers 9 is reduced, the sensitivity and the SN ratio are hardly reduced. Therefore, when applied to a magnetic head for reproducing magnetic information, it is possible to cope with ultra-high density recording in which the recording density exceeds several hundred Gbpsi to 1 Tbpsi.

本実施形態では、強磁性層の一例として、１Ｔｂ／ｉｎｃｈ２対応の読出用磁気ヘッドを想定して強磁性層９は平面積が約３０×３０ｎｍ２、厚さが約１ｎｍとした。なお、強磁性層５と非磁性層７も強磁性層９の平面積と同じにすることができる。つまり、本実施形態の共鳴磁気抵抗効果素子の接合面積は、約３０×３０ｎｍ２となる。また、本実施形態では、強磁性層５、非磁性層７および強磁性層９からなる積層膜４は底面が正方形の柱体をなすように形成されており、その四方側面は非磁性絶縁体（図示せず）で囲まれている。この積層膜４の形状は、底面が円の円柱、底面が三角形の三角柱、底面が多角形の多角柱などの他の形状に適宜変形することがきる。 In this embodiment, assuming that a read magnetic head compatible with 1 Tb / inch 2 is assumed as an example of the ferromagnetic layer, the ferromagnetic layer 9 has a plane area of about 30 × 30 nm 2 and a thickness of about 1 nm. The ferromagnetic layer 5 and the nonmagnetic layer 7 can have the same plane area as the ferromagnetic layer 9. That is, the junction area of the resonant magnetoresistive element of this embodiment is about 30 × 30 nm 2 . In this embodiment, the laminated film 4 composed of the ferromagnetic layer 5, the nonmagnetic layer 7, and the ferromagnetic layer 9 is formed so as to form a column with a square bottom surface, and the four side surfaces thereof are nonmagnetic insulators. (Not shown). The shape of the laminated film 4 can be appropriately changed to other shapes such as a circular cylinder with a bottom surface, a triangular prism with a triangular bottom surface, and a polygonal column with a polygonal bottom surface.

強磁性層９の材料として、Ｆｅ、Ｃｏ、Ｎｉ及びそれらの合金や、Ｃｕ２ＭｎＡｌ、Ｎｉ２ＭｎＩｎ、Ｃｕ２ＭｎＩｎ、Ｃｕ２ＭｎＳｎ、Ｎｉ２ＭｎＳｎ、Ｃｏ２ＭｎＳｎなどのホイスラー合金や、Ｆｅ３Ｏ４、ＬａＳｒＭｎＯ３等の導電性磁性化合物を用いることができる。しかし、後に式で示すように磁化の熱ゆらぎの大きさが磁性体の体積および磁化の平方根に反比例するので磁化が１０００Ｇ以下で厚さが０．１ｎｍ以上３ｎｍ以下の強磁性体が好ましい。非磁性層７の材料としては、Ａｌ、Ｐｔ、Ａｕ、Ａｇ、Ｃｕ等の貴金属、あるいはＣｒ、Ｒｕ、Ｐｄ等の非磁性遷移金属等を用いることができる。非磁性層７の厚さは約１ｎｍから数１０ｎｍ、例えば約５ｎｍとすることができる。非磁性層７は、強磁性層９と強磁性層５との間に働く交換相互作用を遮断し、同時に強磁性層９に発生した伝導電子のスピンゆらぎを強磁性層５へ輸送する役目を担っている。 Examples of the material of the ferromagnetic layer 9 include Fe, Co, Ni, and alloys thereof, Heusler alloys such as Cu 2 MnAl, Ni 2 MnIn, Cu 2 MnIn, Cu 2 MnSn, Ni 2 MnSn, and Co 2 MnSn, Fe 3 Conductive magnetic compounds such as O 4 and LaSrMnO 3 can be used. However, since the magnitude of the thermal fluctuation of the magnetization is inversely proportional to the volume of the magnetic material and the square root of the magnetization as will be shown later, a ferromagnetic material having a magnetization of 1000 G or less and a thickness of 0.1 nm to 3 nm is preferable. As a material of the nonmagnetic layer 7, a noble metal such as Al, Pt, Au, Ag, or Cu, or a nonmagnetic transition metal such as Cr, Ru, or Pd can be used. The thickness of the nonmagnetic layer 7 can be about 1 nm to several tens of nm, for example, about 5 nm. The nonmagnetic layer 7 serves to block the exchange interaction between the ferromagnetic layer 9 and the ferromagnetic layer 5 and simultaneously transport the spin fluctuation of the conduction electrons generated in the ferromagnetic layer 9 to the ferromagnetic layer 5. I'm in charge.

強磁性層５の材料として、例えば六方晶系のＣｏなどを用いることができる。Ｃｏを用いた場合、下地金属の種類や膜厚を制御することによりその垂直異方性磁場（垂直異方性定数）を変化させることができる。強磁性層９が発生する数ＧＨｚ〜数１０ＧＨｚの磁気ゆらぎに共鳴するためには垂直異方性磁場の大きさが１ｋＯｅ以上であることが望ましい。強磁性層５の材料としてＣｏ以外では、ＣｏＣｒＴａ，ＣｏＣｒＴａＰｔ，ＣｏＣｒＴａＮｂなどのＣｏＣｒ系合金、Ｃｏ／Ｐｄ，Ｃｏ／Ｐｔ，Ｃｏ−Ｃｒ−Ｔａ／ＰｄなどのＣｏ多層膜、ＣｏＣｒＰｔ系合金、ＦｅＰｔ系合金、さらに希土類を含むＳｍＣｏ系合金やＴｂＦｅＣｏ合金などが利用できる。また強磁性層５の厚さは後に述べる理由により０．１以上３ｎｍ以下が好ましい。   As the material of the ferromagnetic layer 5, for example, hexagonal Co can be used. When Co is used, the vertical anisotropy magnetic field (vertical anisotropy constant) can be changed by controlling the type and film thickness of the underlying metal. In order to resonate with magnetic fluctuations of several GHz to several tens of GHz generated by the ferromagnetic layer 9, the magnitude of the perpendicular anisotropic magnetic field is desirably 1 kOe or more. Other than Co as the material of the ferromagnetic layer 5, CoCr alloys such as CoCrTa, CoCrTaPt, and CoCrTaNb, Co multilayer films such as Co / Pd, Co / Pt, and Co—Cr—Ta / Pd, CoCrPt alloys, and FePt alloys Furthermore, rare earth-containing SmCo alloys and TbFeCo alloys can be used. The thickness of the ferromagnetic layer 5 is preferably 0.1 to 3 nm for the reason described later.

下部電極３および上部電極１１の材料には、Ａｌ、Ｃｕ、Ａｕ、Ａｇ、Ｒｕ等の金属を使用する。特にＣｏを強磁性層５として用いる場合にはＲｕを用いることが好ましい。また、下部電極３および上部電極１１が磁気シールドを兼ねる場合には、上記の金属からなる膜とＮｉＦｅ等の公知のシールド材料膜とのを積層膜を形成する。なお、基板１にはシリコンやＳｉＯ２・Ａｌ２Ｏ３・ＴｉＣなどの非磁性絶縁体の基板など、一般に磁気素子を形成するに適した基板材料を用いる。 As the material of the lower electrode 3 and the upper electrode 11, a metal such as Al, Cu, Au, Ag, Ru is used. In particular, when Co is used as the ferromagnetic layer 5, it is preferable to use Ru. When the lower electrode 3 and the upper electrode 11 also serve as a magnetic shield, a laminated film is formed of the above-described metal film and a known shield material film such as NiFe. For the substrate 1, a substrate material generally suitable for forming a magnetic element, such as a substrate of nonmagnetic insulator such as silicon or SiO 2 / Al 2 O 3 / TiC, is used.

次に、強磁性層９における磁化の熱ゆらぎについて説明する。図２（ａ）は、強磁性層９の熱ゆらぎのパワースペクトルＳ<mt>を模式的に示した図である。図２（ｂ）は、強磁性層９の膜面内の磁化成分を示しており、Ｍsは強磁性層９の飽和磁化、Ｍtは強磁性層９の磁化の飽和磁化と直交する横成分である。Ｍtと飽和磁化Ｍsとの比であるｍtは強磁性層９の磁化の熱ゆらぎの角度（radian）を表している。温度Ｔ（Kelvin）における強磁性層９の磁化の熱ゆらぎは、ｍt（＝Ｍt／Ｍs）の二乗平均＜ｍt 2＞のパワースペクトルＳ<mt>を用いて近似的に（１）式のように表される。

Figure 0005032009
Next, the thermal fluctuation of magnetization in the ferromagnetic layer 9 will be described. FIG. 2A is a diagram schematically showing a power spectrum S <mt> of thermal fluctuation of the ferromagnetic layer 9. FIG. 2B shows the magnetization component in the film surface of the ferromagnetic layer 9, where M s is the saturation magnetization of the ferromagnetic layer 9, and M t is the transverse magnetization perpendicular to the saturation magnetization of the magnetization of the ferromagnetic layer 9. It is an ingredient. Which is the ratio of the M t and the saturation magnetization M s m t represents the angle (radian) of the thermal fluctuation of the magnetization of the ferromagnetic layer 9. The thermal fluctuation of the magnetization of the ferromagnetic layer 9 at the temperature T (Kelvin) is approximately (1) using the power spectrum S <mt> of the root mean square <m t 2 > of m t (= M t / M s ). )
Figure 0005032009

（１）式中、χ"FMは強磁性層９の高周波帯磁率の虚数部、ＶFMは強磁性層９の体積、αは強磁性層９のギルバートの減衰係数、γ（＝１９×１０６ｒａｄ／ｓＯｅ）はジャイロ磁気比、ｆＦＭは強磁性層９の共鳴周波数、Ｈは強磁性層９が受ける外部磁場、ＨKは強磁性層９の異方性磁場である。（１）式および図２（ａ）から、外部磁場周波数ｆが共鳴周波数ｆＦＭ近傍において、高周波帯磁率χ"FMが増大し、強磁性層９の磁化ゆらぎのパワースペクトルＳ<mt>も増大することが分かる。Ｓ<mt>のピーク周波数ｆＦＭでの値は体積ＶFMおよび飽和磁化Ｍsに反比例する。強磁性層９として体積ＶFMが約３０×３０×１ｎｍ３のパーマロイ（飽和磁化Ｍｓ＝８００Ｇａｕｓｓ）を用いた場合、共鳴周波数ｆ０＝１０ＧＨｚ、ギルバートの減衰係数α＝０．０１とすると、外部磁場の周波数ｆ＝ｆＦＭ、バンド幅Δｆにおける強磁性層９の磁化の熱ゆらぎ＜ｍt 2＞1/2は（２）式のようになる。

Figure 0005032009
In the equation (1), χ ″ FM is the imaginary part of the high-frequency magnetic susceptibility of the ferromagnetic layer 9, V FM is the volume of the ferromagnetic layer 9, α is the Gilbert attenuation coefficient of the ferromagnetic layer 9, and γ (= 19 × 10 6 rad / SOE) is the gyromagnetic ratio, f FM is the resonant frequency of the ferromagnetic layer 9, H is the external magnetic field, H K of the ferromagnetic layer 9 undergoes an anisotropy field of the ferromagnetic layer 9. (1) From the equation and FIG. 2A, when the external magnetic field frequency f is in the vicinity of the resonance frequency f FM , the high-frequency magnetic susceptibility χ ″ FM increases and the power spectrum S <mt> of the magnetization fluctuation of the ferromagnetic layer 9 also increases. I understand. The value of S <mt> at the peak frequency f FM is inversely proportional to the volume V FM and the saturation magnetization M s . When a permalloy (saturated magnetization M s = 800 Gauss) having a volume V FM of about 30 × 30 × 1 nm 3 is used as the ferromagnetic layer 9, assuming that the resonance frequency f 0 = 10 GHz and Gilbert's attenuation coefficient α = 0.01, The thermal fluctuation <m t 2 > 1/2 of the magnetization of the ferromagnetic layer 9 at the frequency f = f FM of the external magnetic field and the bandwidth Δf is expressed by equation (2).
Figure 0005032009

ここで、バンド幅Δｆは強磁性層９の共鳴線の全半値幅であって

Figure 0005032009
と表され、Δｆ＝５．６×１０８Ｈｚである。 Here, the bandwidth Δf is the full width at half maximum of the resonance line of the ferromagnetic layer 9.
Figure 0005032009
 And Δf = 5.6 × 10 8 Hz.

このような磁化のゆらぎを持つ強磁性層９の中の伝導電子には、強磁性層９の磁化の熱ゆらぎに起因するスピンゆらぎが生じる。このスピンゆらぎを持つ伝導電子は、強磁性層９／非磁性層７／強磁性層５からなる積層膜４に流れる電流により輸送されて非磁性層７を通過して強磁性層５に注入される。注入された伝導電子のスピンゆらぎは、ｓｄ交換相互作用などを介して強磁性層５に高周波トルク（実効高周波磁場）を及ぼし、強磁性層５に磁気共鳴を誘起する。スピンｓが磁性体に及ぼすトルクは（３）式で表される。

Figure 0005032009
In the conduction electrons in the ferromagnetic layer 9 having such magnetization fluctuations, spin fluctuations caused by thermal fluctuations in the magnetization of the ferromagnetic layer 9 occur. The conduction electrons having the spin fluctuation are transported by the current flowing through the laminated film 4 composed of the ferromagnetic layer 9 / nonmagnetic layer 7 / ferromagnetic layer 5, pass through the nonmagnetic layer 7 and injected into the ferromagnetic layer 5. The The spin fluctuation of the injected conduction electrons applies a high frequency torque (effective high frequency magnetic field) to the ferromagnetic layer 5 through sd exchange interaction and the like, and induces magnetic resonance in the ferromagnetic layer 5. The torque that the spin s exerts on the magnetic material is expressed by equation (3).
Figure 0005032009

（３）式において太字のＭは強磁性層５の磁化ベクトルであり、Ｍハットおよびｓハットは磁化ベクトルＭおよびスピンｓ方向の単位ベクトルである。ｈ＝（ｈ１ ２＋ｈ２ ２）１／２は実効磁場の大きさである。ｈは電流密度ｊ、電流のスピン分極率ｐ、強磁性層５の厚さｄ、および磁化ベクトルの大きさである磁化Ｍに依存する。厚さｄが薄いほど、また磁化Ｍが小さいほどｈは大きくなるので厚さｄは０．１ｎｍ以上３ｎｍ以下、磁化Ｍは１０００Ｇ以下とすることが望ましい。電流のスピン分極率ｐは０．８程度であり、ｄ＝１ｎｍ、Ｍ＝１０００Ｇでは、ｊ（Ａ／ｃｍ２）の電流密度の下でｈ＝１０−４ｊ（Ｏｅ）程度である。 In equation (3), bold M is a magnetization vector of the ferromagnetic layer 5, and M hat and s hat are a magnetization vector M and a unit vector in the spin s direction. h = (h 1 2 + h 2 2 ) 1/2 is the magnitude of the effective magnetic field. h depends on the current density j, the spin polarizability p of the current, the thickness d of the ferromagnetic layer 5, and the magnetization M which is the magnitude of the magnetization vector. As the thickness d is thinner and the magnetization M is smaller, h becomes larger. Therefore, it is desirable that the thickness d is 0.1 nm or more and 3 nm or less, and the magnetization M is 1000 G or less. The spin polarizability p of the current is about 0.8, and when d = 1 nm and M = 1000 G, h = 10 −4 j (Oe) at a current density of j (A / cm 2 ).

（３）式からスピンゆらぎ＜ｍｔ ２＞によって生じる高周波磁場のパワースペクトルはＧ（ｆ）＝ｈ２Ｓ＜ｍｔ＞となる。 From the equation (3), the power spectrum of the high-frequency magnetic field generated by the spin fluctuation <m t 2 > is G (f) = h 2 S <mt> .

強磁性層５の帯磁率の虚数部は（４）式で表される。

Figure 0005032009
The imaginary part of the magnetic susceptibility of the ferromagnetic layer 5 is expressed by equation (4).
Figure 0005032009

（４）式においてｆ０は強磁性層５の共鳴周波数、ＨAは異方性磁場、α´は強磁性層５のギルバートの減衰定数であり、ＨＡ−４πＭ＝３５００（Ｏｅ）のＣｏを強磁性層５に用いた場合ｆ０≒１０ＧＨｚとなる。 In Equation (4), f 0 is the resonance frequency of the ferromagnetic layer 5, H A is the anisotropic magnetic field, α ′ is the Gilbert damping constant of the ferromagnetic layer 5, and Co of H A −4πM = 3500 (Oe) Is used for the ferromagnetic layer 5, f 0 ≈10 GHz.

通常の強磁性共鳴の場合ように磁化の向きが膜面に垂直な強磁性層５の磁化の熱ゆらぎが小さく無視できる場合には、強磁性層５および強磁性層９の共鳴周波数が等しければ上述の高周波磁場はその大きさにかかわらず強磁性層５に磁気共鳴を誘起することができる。しかしながら現在の素子では強磁性層５の熱ゆらぎは大きく、強磁性層９の熱ゆらぎと同程度である。強磁性層９および強磁性層５における磁化の熱ゆらぎには位相の相関がなく、また位相の相関時間も１／（αｆＦＭ）＝１／（α'ｆＰＦＭ）程度なので、高周波磁場が小さい場合には時間平均するとエネルギーの吸収は生じない。しかしながら電流が増加するとそれに比例して高周波磁場が増大するため、強磁性層５の磁化Ｍの運動は高周波磁場に支配されるようになり、ついには高周波磁場と同位相になりエネルギー吸収が生じる。ｈ＝ｈ０・ｊとすると、強磁性層９および強磁性層５の厚さが等しい場合、共鳴吸収が生じる閾値電流密度は（５）式で表される。

Figure 0005032009
When the thermal fluctuation of the magnetization of the ferromagnetic layer 5 whose direction of magnetization is perpendicular to the film surface is small and can be ignored as in the case of normal ferromagnetic resonance, the resonance frequency of the ferromagnetic layer 5 and the ferromagnetic layer 9 should be equal. The above-described high-frequency magnetic field can induce magnetic resonance in the ferromagnetic layer 5 regardless of its magnitude. However, in the present element, the thermal fluctuation of the ferromagnetic layer 5 is large and is about the same as the thermal fluctuation of the ferromagnetic layer 9. The thermal fluctuation of magnetization in the ferromagnetic layer 9 and the ferromagnetic layer 5 has no phase correlation, and the phase correlation time is also about 1 / (αf FM ) = 1 / (α′f PFM ), so the high frequency magnetic field is small. In some cases, no energy absorption occurs when time averaged. However, when the current increases, the high-frequency magnetic field increases in proportion thereto, so that the movement of the magnetization M of the ferromagnetic layer 5 is dominated by the high-frequency magnetic field, and finally becomes in phase with the high-frequency magnetic field and energy absorption occurs. When h = h 0 · j, when the thicknesses of the ferromagnetic layer 9 and the ferromagnetic layer 5 are equal, the threshold current density at which resonance absorption occurs is expressed by equation (5).
Figure 0005032009

ｐ＝０．８、Ｍ＝１０００Ｇ、ｄ＝１ｎｍの場合ｈ０＝１．４×１０−４Ｏｅ／（Ａ／ｃｍ２）と見積もられるので、臨界電流密度ｊｔｈは、ｊｔｈ＝２．８×１０４Ａ／ｃｍ２となる。ｈ０は磁性層の膜厚に反比例するので膜厚が薄いほど低い閾値電流密度で共鳴吸収を起こすことができる。ｈ０が膜厚に依存するため閾値電流は強磁性層９および強磁性層５の厚さには依存するが、（５）式から分かるように素子面積に依存しない。 In the case of p = 0.8, M = 1000 G, and d = 1 nm, it is estimated that h 0 = 1.4 × 10 −4 Oe / (A / cm 2 ), so that the critical current density j th is j th = 2. 8 × 10 4 A / cm 2 . h 0 can cause a resonance absorption at a low threshold current density as a thin film thickness is inversely proportional to the thickness of the magnetic layer. The threshold current for the h 0 is dependent on the film thickness depends on the thickness of the ferromagnetic layer 9 and the ferromagnetic layer 5, but does not depend on the element area as seen from the equation (5).

電流密度ｊが臨界電流密度ｊｔｈ以上では強磁性層５のゆらぎは強磁性層９のゆらぎと同位相になっているので、この高周波トルクにより強磁性層９のゆらぎはさらに増大する。すなわちｊ＞ｊｔｈでは強磁性層５の磁化と強磁性層９の磁化の運動の間に正帰還ループが形成され、ゆらぎの振幅は磁化の大きさＭとほぼ等しくなるまで増大する。 Since the current density j is a critical current density j th least fluctuation of the ferromagnetic layer 5 is in the same phase and fluctuations of the ferromagnetic layer 9, the fluctuation of the ferromagnetic layer 9 by the high-frequency torque further increases. That is, when j> j th , a positive feedback loop is formed between the magnetization of the ferromagnetic layer 5 and the magnetization movement of the ferromagnetic layer 9, and the amplitude of the fluctuation increases until it becomes substantially equal to the magnitude M of the magnetization.

電流密度ｊが臨海電流密度ｊｔｈ以上での強磁性層５での共鳴吸収パワーは（６）式で評価することができる。

Figure 0005032009
The resonance absorption power in the ferromagnetic layer 5 when the current density j is equal to or greater than the sea current density jth can be evaluated by the equation (6).
Figure 0005032009

Ｍ＝１０００Ｇ、ＶＰＦＭ ＝３０×３０×１ｎｍ３、ｈ＝１．４×１０−４×ｊ Ｏ
ｅを代入するとｊ＝ｊｔｈ＝２．８×１０４Ａ／ｃｍ２における吸収はＷＰＦＭ＝１．１×１０−４ｅｒｇ／ｓ＝１．１×１０−１１ワットとなる。強磁性層５のゆらぎに伴う高周波トルクが強磁性層９に作用する効果を取り入れて、強磁性層９における同量の吸収を加えると素子全体の吸収ＷとしてＷ＝２．２×１０−１１ワットが得られる。素子電圧および抵抗は、素子の平面積がＡ＝３０×３０ｎｍ２であるから、Ｉ≒Ｉｔｈ＝ｊｔｈ・Ａ＝２．５×１０−７ＡにおいてそれぞれΔＶ＝Ｗ／Ｉｔｈ＝０．８８×１０−４ＶおよびΔＲ＝ΔＶ／Ｉｔｈ＝３５０Ωとなる。Ｉ＞Ｉｔｈにおいて吸収パワーはＷ＝８．８×１０−５Ｉのように電流に比例して増大するのでΔＶは一定のままである。非共鳴時の抵抗Ｒ０は界面抵抗を１．０×１０−１１Ωｃｍ２、平均的バルク抵抗を５×１０−６Ωｃｍとすると約５Ωなので、ΔＲ（Ｉｔｈ）／Ｒ０〜７０（７０００％）となる。 M = 1000G, V PFM = 30 × 30 × 1 nm 3 , h = 1.4 × 10 −4 × j O
Substituting e, the absorption at j = j th = 2.8 × 10 4 A / cm 2 is WPFM = 1.1 × 10 −4 erg / s = 1.1 × 10 −11 watts. Taking in the effect that the high frequency torque accompanying the fluctuation of the ferromagnetic layer 5 acts on the ferromagnetic layer 9 and adding the same amount of absorption in the ferromagnetic layer 9, W = 2.2 × 10 −11 as the absorption W of the entire element. Watts are obtained. The element voltage and resistance are such that the plane area of the element is A = 30 × 30 nm 2 , and therefore , ΔV = W / I th = 0.I at I≈I th = j th · A = 2.5 × 10 −7 A. 88 × 10 −4 V and ΔR = ΔV / I th = 350Ω. Absorbing power at I> I th remains ΔV is constant because increases in proportion to the current as W = 8.8 × 10 -5 I. The resistance R 0 at non-resonance is about 5Ω when the interface resistance is 1.0 × 10 −11 Ωcm 2 and the average bulk resistance is 5 × 10 −6 Ωcm, so ΔR (I th ) / R 0 to 70 (7000) %).

（１）式から外部磁場の変化δＨにより、微小磁性体のゆらぎのパワースペクトルのピーク周波数ｆＦＭは（７）式のように変化するが、垂直磁化膜の共鳴周波数はＨ＜＜ＨＡ＝３５００Ｏｅではほとんど変化しない。

Figure 0005032009
From the expression (1), the peak frequency f FM of the fluctuation power spectrum of the micromagnetic material changes as shown in the expression (7) due to the change δH of the external magnetic field, but the resonance frequency of the perpendicular magnetization film is H << HA = Almost no change at 3500 Oe.
Figure 0005032009

すなわち素子は外部磁場を印加することにより共鳴状態から非共鳴状態へと変化し、出力電圧ΔＶは減少する。   That is, the element changes from a resonance state to a non-resonance state by applying an external magnetic field, and the output voltage ΔV decreases.

本実施形態の共鳴磁気抵抗効果素子の特性を図３に示す。外部磁場が変化し共鳴磁気抵抗効果素子が共鳴状態から非共鳴状態に変化すると、点線で示したように閾値電流が変化し、矢印で示したように出力電圧が大きく変化する。   The characteristics of the resonant magnetoresistive element of this embodiment are shown in FIG. When the external magnetic field changes and the resonant magnetoresistive element changes from the resonance state to the non-resonance state, the threshold current changes as indicated by the dotted line, and the output voltage changes significantly as indicated by the arrow.

本実施形態の共鳴磁気抵抗効果素子は磁化の熱ゆらぎを利用しているが、その特性は強磁性層９および磁化の向きが膜面に垂直な強磁性層５における熱ゆらぎの相対的大きさに依存する。このため、それぞれの膜が単磁区構造を有する限り素子サイズには依存せず機能する。しかしながら、磁性体のサイズが小さいほど単磁区構造の磁性層は得られやすいため、１μｍ２以下の素子サイズであることが望ましい。また熱ゆらぎのカットオフ周波数ｋＴ／ｈ（ｋ：ボルツマン定数、Ｔ：温度、ｈ：プランク定数）が共鳴周波数に比べて十分高い温度範囲では特性の温度依存性は小さいので、一般に熱ゆらぎが小さくなる低温においても動作する。 The resonant magnetoresistive element of this embodiment uses thermal fluctuations of magnetization, and the characteristics thereof are the relative magnitude of thermal fluctuations in the ferromagnetic layer 9 and the ferromagnetic layer 5 in which the magnetization direction is perpendicular to the film surface. Depends on. For this reason, as long as each film has a single domain structure, it functions independently of the element size. However, since as the size of the magnetic material is small magnetic layer of a single-domain structure can be easily obtained, it is desirable that the element size of 1 [mu] m 2 or less. In addition, in the temperature range where the cutoff frequency kT / h (k: Boltzmann constant, T: temperature, h: Planck constant) of the thermal fluctuation is sufficiently higher than the resonance frequency, the temperature dependence of the characteristics is small, so the thermal fluctuation is generally small. It operates even at low temperatures.

次に、本実施形態による共鳴磁気抵抗効果素子の電気的、磁気的ノイズについて述べる。図１に示す共鳴磁気抵抗効果素子は多数の強磁性体と非磁性体の界面を含むが、素子にかかる全電圧Ｖ0は数ｍＶ程度なので、ｅＶ0＜＜ｋＴの関係が成り立ち、電気的ノイズとしては（８）式で表される熱雑音ｖelが支配的となる。

Figure 0005032009
Next, electrical and magnetic noise of the resonant magnetoresistive element according to the present embodiment will be described. The resonant magnetoresistive element shown in FIG. 1 includes a large number of ferromagnetic and nonmagnetic interfaces. However, since the total voltage V 0 applied to the element is about several mV, the relationship of eV 0 << kT is established, As the noise, the thermal noise vel expressed by the equation (8) becomes dominant.
Figure 0005032009

ここでＢはバンド幅である。またこの素子の磁気的白色雑音は０．１μＶ以下となり無視することができる。Ｂ＝３００ＭＨｚ、Ｒ０＝５Ω、ΔＶ＝０．１ｍＶの場合、ＳＮ比（ＳＮＲ）は、ＳＮＲ＝ΔＶ／ｖelと表され、ＳＮＲ＝２０（２６ｄＢ）となる。 Here, B is a bandwidth. The magnetic white noise of this element is 0.1 μV or less and can be ignored. B = 300MHz, R 0 = 5Ω , if the [Delta] V = 0.1 mV, SN ratio (SNR) is expressed as SNR = ΔV / v el, the SNR = 20 (26dB).

以上説明したように、本実施形態によれば、磁気的白色雑音を可及的に抑制することができる。   As described above, according to the present embodiment, magnetic white noise can be suppressed as much as possible.

なお、本実施形態の共鳴磁気抵抗効果素子を磁気ヘッドの再生素子として用いる場合は、図８に示すように、強磁性層５、非磁性層７および強磁性層９からなる積層膜４の側部に水平磁化バイアス膜２０を設けることが必要となる。   When the resonant magnetoresistive element of this embodiment is used as a reproducing element of a magnetic head, as shown in FIG. 8, the side of the laminated film 4 composed of the ferromagnetic layer 5, the nonmagnetic layer 7, and the ferromagnetic layer 9 is used. It is necessary to provide the horizontal magnetization bias film 20 in the part.

（第２実施形態）
第１実施形態では強磁性層９と磁化の向きが膜面に実質的に垂直な強磁性層５がそれぞれ単層であって、非磁性層７を介して形成された積層膜４を１個有する共鳴磁気抵抗効果素子であった。 (Second Embodiment)
In the first embodiment, the ferromagnetic layer 9 and the ferromagnetic layer 5 whose magnetization direction is substantially perpendicular to the film surface are each a single layer, and one laminated film 4 formed via the nonmagnetic layer 7 is provided. It was a resonance magnetoresistive effect element.

本実施形態の共鳴磁気抵抗効果素子は、第１実施形態の積層膜４を複数個積層した構造を有している。第１実施形態の積層膜を複数個積層することにより磁化の向きが膜面に実質的に平行な強磁性層によって生じたスピンゆらぎが磁化の向きが膜面に垂直な強磁性層に順次、共鳴を誘起することにより、より大きな出力電圧ΔＶを得ることができる。図４（ａ）に示すように、磁化の向きが膜面に実質的に垂直な強磁性層５と、磁化の向きが膜面に実質的に平行な強磁性層９を非磁性層７を介して交互に積層することが好ましいが、図４（ｂ）に示すように磁化の向きが膜面に実質的に平行な２層の強磁性層９の間に、磁化の向きが膜面に実質的に垂直な強磁性層５を非磁性層７を介して複数層積層しても出力電圧を第１実施形態に比べて大きくすることができる。   The resonant magnetoresistive effect element according to the present embodiment has a structure in which a plurality of stacked films 4 according to the first embodiment are stacked. By laminating a plurality of the laminated films of the first embodiment, spin fluctuations caused by the ferromagnetic layer whose magnetization direction is substantially parallel to the film surface are sequentially applied to the ferromagnetic layer whose magnetization direction is perpendicular to the film surface. By inducing resonance, a larger output voltage ΔV can be obtained. As shown in FIG. 4A, a ferromagnetic layer 5 whose magnetization direction is substantially perpendicular to the film surface, a ferromagnetic layer 9 whose magnetization direction is substantially parallel to the film surface, and a nonmagnetic layer 7 However, as shown in FIG. 4B, the magnetization direction is between the two ferromagnetic layers 9 substantially parallel to the film surface and the magnetization direction is on the film surface. Even when a plurality of substantially perpendicular ferromagnetic layers 5 are laminated via the nonmagnetic layer 7, the output voltage can be increased as compared with the first embodiment.

この実施形態も、第１実施形態と同様に磁気的白色雑音を可及的に抑制することができる。   This embodiment can also suppress magnetic white noise as much as possible as in the first embodiment.

（第３実施形態）
次に、本発明の第３実施形態による共鳴磁気抵抗効果素子を図９を参照して説明する。本実施形態の共鳴磁気抵抗効果素子は、第１または第２実施形態の共鳴磁気抵抗効果素子において、強磁性層９と上部電極１１との間に垂直磁化バイアス膜２２を設けた構成となっている。 (Third embodiment)
Next, a resonant magnetoresistive element according to a third embodiment of the invention will be described with reference to FIG. The resonant magnetoresistive element of this embodiment has a configuration in which a perpendicular magnetization bias film 22 is provided between the ferromagnetic layer 9 and the upper electrode 11 in the resonant magnetoresistive element of the first or second embodiment. Yes.

第１、第２の実施形態においては、強磁性層５の面内に印加された外部磁場の変化を（７）式で示される強磁性層５の共鳴周波数の変化として検知するが、第３実施形態では強磁性層９の共鳴周波数の変化として検出する。磁化が垂直な強磁性層５の共鳴周波数の磁場変化は形状異方性磁場４πＭと膜面に垂直方向の結晶異方性磁場ＨＡとの差が小さいほど大きい。このため、本実施形態の共鳴磁気抵抗効果素子をセンサとして用いる場合は０Ｏｅ≦（ＨＡ−４πＭ ）≦５００Ｏｅであることが望ましい。また強磁性層９についても形状異方性磁場４πＭｓと膜面に垂直方向の結晶異方性磁場ＨＡ１との差を小さくすることにより、膜面に垂直方向の磁場変化を検知することができるが、高い感度を持つためには０Ｏｅ≦（４πＭｓ−ＨＡ１）≦５００Ｏｅであることが望ましい。この場合、垂直磁化バイアス膜２２からのバイアス磁場により磁性層９の磁化の方向を膜面に実質的に垂直に向けた状態でセンサとして機能させることにより、さらに高い感度が得られる。 In the first and second embodiments, a change in the external magnetic field applied in the plane of the ferromagnetic layer 5 is detected as a change in the resonance frequency of the ferromagnetic layer 5 expressed by equation (7). In the embodiment, it is detected as a change in the resonance frequency of the ferromagnetic layer 9. Magnetization is greater the smaller the difference between the vertical direction of the crystal anisotropy field H A in magnetic field change the shape anisotropy field 4πM the film surface of the resonant frequency of the vertical ferromagnetic layer 5. For this reason, when the resonant magnetoresistive element of this embodiment is used as a sensor, 0 Oe ≦ ( HA −4πM ) ≦ 500 Oe. In the ferromagnetic layer 9 as well, the magnetic field change in the direction perpendicular to the film surface can be detected by reducing the difference between the shape anisotropy field 4πM s and the crystal anisotropy magnetic field H A1 in the direction perpendicular to the film surface. However, in order to have high sensitivity, it is desirable that 0Oe ≦ (4πM s −H A1 ) ≦ 500 Oe. In this case, higher sensitivity can be obtained by causing the magnetic layer 9 to function as a sensor in a state in which the magnetization direction of the magnetic layer 9 is substantially perpendicular to the film surface by the bias magnetic field from the perpendicular magnetization bias film 22.

なお、本実施形態においては、強磁性層９と上部電極１１との間に垂直磁化バイアス膜２２を設けたが、図１０に示すように、強磁性層５、非磁性層７および強磁性層９の積層膜４の側部に垂直磁化バイアス膜２４を設けてもよい。   In this embodiment, the perpendicular magnetization bias film 22 is provided between the ferromagnetic layer 9 and the upper electrode 11. However, as shown in FIG. 10, the ferromagnetic layer 5, the nonmagnetic layer 7, and the ferromagnetic layer are provided. The perpendicular magnetization bias film 24 may be provided on the side of the laminated film 4.

（第４実施形態）
次に、本発明の第４実施形態による磁気記録再生装置について説明する。図１乃至図１０に関して説明した第１乃至第３実施形態による共鳴磁気抵抗効果素子を再生素子として備えた磁気ヘッドは、例えば、記録再生一体型の磁気ヘッドアセンブリに組み込まれ、磁気記録再生装置に搭載することができる。 (Fourth embodiment)
Next explained is a magnetic recording / reproducing apparatus according to the fourth embodiment of the invention. A magnetic head provided with the resonant magnetoresistive effect element according to the first to third embodiments described with reference to FIGS. 1 to 10 as a reproducing element is incorporated into a recording / reproducing integrated magnetic head assembly, for example, in a magnetic recording / reproducing apparatus. Can be installed.

図１１は、このような磁気記録再生装置の概略構成を例示する要部斜視図である。すなわち、本実施形態による磁気記録再生装置１５０は、ロータリーアクチュエータを用いた形式の装置である。同図において、長手記録用または垂直記録用磁気ディスク２００は、スピンドル１５２に装着され、図示しない駆動装置制御部からの制御信号に応答する図示しないモータにより矢印Ａの方向に回転する。磁気ディスク２００は、長手記録用または垂直記録用の記録層を有する。磁気ディスク２００は、磁気ディスク２００に格納される情報の記録再生を行うヘッドスライダ１５３は、薄膜状のサスペンション１５４の先端に取り付けられている。ここで、ヘッドスライダ１５３は、前述したいずれかの実施形態による共鳴磁気抵抗効果素子を再生素子として備えた磁気ヘッドをその先端付近に搭載している。   FIG. 11 is a perspective view of a main part illustrating the schematic configuration of such a magnetic recording / reproducing apparatus. That is, the magnetic recording / reproducing apparatus 150 according to the present embodiment is an apparatus using a rotary actuator. In the figure, a magnetic disk 200 for longitudinal recording or perpendicular recording is mounted on a spindle 152 and rotated in the direction of arrow A by a motor (not shown) that responds to a control signal from a drive device control unit (not shown). The magnetic disk 200 has a recording layer for longitudinal recording or perpendicular recording. In the magnetic disk 200, a head slider 153 that records and reproduces information stored in the magnetic disk 200 is attached to the tip of a thin film suspension 154. Here, the head slider 153 has a magnetic head equipped with the resonant magnetoresistive element according to any one of the above-described embodiments as a reproducing element mounted near the tip thereof.

磁気ディスク２００が回転すると、ヘッドスライダ１５３の媒体走行面（ＡＢＳ）は磁気ディスク２００の表面から所定の浮上量をもって保持される。   When the magnetic disk 200 rotates, the medium running surface (ABS) of the head slider 153 is held with a predetermined flying height from the surface of the magnetic disk 200.

サスペンション１５４は、図示しない駆動コイルを保持するボビン部などを有するアクチュエータアーム１５５の一端に接続されている。アクチュエータアーム１５５の他端には、リニアモータの一種であるボイスコイルモータ１５６が設けられている。ボイスコイルモータ１５６は、アクチュエータアーム１５５のボビン部に巻き上げられた図示しない駆動コイルと、このコイルを挟み込むように対向して配置された永久磁石および対向ヨークからなる磁気回路とから構成される。   The suspension 154 is connected to one end of an actuator arm 155 having a bobbin portion for holding a drive coil (not shown). A voice coil motor 156, which is a kind of linear motor, is provided at the other end of the actuator arm 155. The voice coil motor 156 is composed of a drive coil (not shown) wound around the bobbin portion of the actuator arm 155, and a magnetic circuit composed of a permanent magnet and a counter yoke arranged so as to sandwich the coil.

アクチュエータアーム１５５は、固定軸１５７の上下２箇所に設けられた図示しないボールベアリングによって保持され、ボイスコイルモータ１５６により回転摺動が自在にできるようになっている。   The actuator arm 155 is held by ball bearings (not shown) provided at two locations above and below the fixed shaft 157, and can be freely rotated and slid by a voice coil motor 156.

図１２は、アクチュエータアーム１５５から先の磁気ヘッドアセンブリをディスク側から眺めた拡大斜視図である。すなわち、磁気ヘッドアッセンブリ１６０は、例えば駆動コイルを保持するボビン部などを有するアクチュエータアーム１５５を有し、アクチュエータアーム１５５の一端にはサスペンション１５４が接続されている。   FIG. 12 is an enlarged perspective view of the magnetic head assembly ahead of the actuator arm 155 as viewed from the disk side. That is, the magnetic head assembly 160 includes an actuator arm 155 having, for example, a bobbin portion that holds a drive coil, and a suspension 154 is connected to one end of the actuator arm 155.

サスペンション１５４の先端には、前述したいずれかの磁気ヘッドを具備するヘッドスライダ１５３が取り付けられている。再生用ヘッドを組み合わせても良い。サスペンション１５４は信号の書き込みおよび読み取り用のリード線１６４を有し、このリード線１６４とヘッドスライダ１５３に組み込まれた磁気ヘッドの各電極とが電気的に接続されている。図中１６５は磁気ヘッドアッセンブリ１６０の電極パッドである。   A head slider 153 including any of the magnetic heads described above is attached to the tip of the suspension 154. A reproducing head may be combined. The suspension 154 has a lead wire 164 for writing and reading signals, and the lead wire 164 and each electrode of the magnetic head incorporated in the head slider 153 are electrically connected. In the figure, reference numeral 165 denotes an electrode pad of the magnetic head assembly 160.

次に、本発明の実施例を説明する。   Next, examples of the present invention will be described.

（実施例１）
次に、本発明の実施例１による共鳴磁気抵抗効果素子の構成を図５に示す。図５は本実施例の構成を示す断面図である。本実施例の共鳴磁気抵抗効果素子は以下のように作製される。 Example 1
Next, the configuration of the resonant magnetoresistive element according to Example 1 of the present invention is shown in FIG. FIG. 5 is a cross-sectional view showing the configuration of this embodiment. The resonant magnetoresistive element of the present example is manufactured as follows.

スパッタ成膜と電子線リソグラフィーを用いてサファイア基板１上に積層膜を形成した。この積層膜は、基板１側から順に、Ｒｕからなる非磁性層３、Ｃｏからなる強磁性層５、Ｃｕからなる非磁性層７、Ｆｅからなる強磁性層９、Ｃｕからなる非磁性層１３、Ｔａからなる非磁性層１５、Ｃｕからなる非磁性層を有する。   A laminated film was formed on the sapphire substrate 1 using sputtering film formation and electron beam lithography. The laminated film includes, in order from the substrate 1 side, a nonmagnetic layer 3 made of Ru, a ferromagnetic layer 5 made of Co, a nonmagnetic layer 7 made of Cu, a ferromagnetic layer 9 made of Fe, and a nonmagnetic layer 13 made of Cu. , Ta nonmagnetic layer 15 and Cu nonmagnetic layer.

各層の厚さは、Ｒｕ層３が約１００ｎｍ、Ｃｏ層５が約１ｎｍ、Ｃｕ層７が約１０ｎｍ、Ｆｅ層９が約１ｎｍ、Ｃｕ層１３が約１０ｎｍ、Ｔａ層１５が約２０ｎｍ、Ｃｕ層１１が約１００ｎｍとした。強磁性のＣｏ層５、Ｆｅ層９と非磁性のＣｕ層７、１３との各接合面積は約１００×１００ｎｍ２とし、層間絶縁膜にはＳｉＯ２を用いた。 The thickness of each layer is about 100 nm for the Ru layer 3, about 1 nm for the Co layer 5, about 10 nm for the Cu layer 7, about 1 nm for the Fe layer 9, about 10 nm for the Cu layer 13, about 20 nm for the Ta layer 15, Cu layer 11 was about 100 nm. Each junction area of the ferromagnetic Co layer 5 and Fe layer 9 and the nonmagnetic Cu layers 7 and 13 was about 100 × 100 nm 2, and SiO 2 was used for the interlayer insulating film.

Ｃｏ層５は磁化の向きが膜面に実質的に垂直な強磁性層であり、磁化の向きが膜面に実質的に平行な強磁性層であるＦｅ層９の形成は、約１０００Ｏｅの磁場を膜面に平行方向に印加しながら成膜することで磁気的一軸異方性を付与した。Ｃｏ層５およびＦｅ層９の磁気特性は素子作製と同一条件で作製したＲｕ層３／Ｃｏ層５／Ｃｕ層７からなる積層膜およびＣｕ層７／Ｆｅ層９／Ｃｕ層１３からなる積層膜の磁化測定および強磁性共鳴測定により調べた。Ｃｏ層５の磁化は９２０Ｇ、膜面に垂直な異方性磁場の大きさは３５００Ｏｅであり、Ｆｅ層９の磁化は１０５０Ｇ、膜面に平行な異方性磁場の大きさは４１０Ｏｅであった。   The Co layer 5 is a ferromagnetic layer whose magnetization direction is substantially perpendicular to the film surface, and the formation of the Fe layer 9 which is a ferromagnetic layer whose magnetization direction is substantially parallel to the film surface is a magnetic field of about 1000 Oe. Magnetic uniaxial anisotropy was imparted by applying the film in a direction parallel to the film surface. The magnetic characteristics of the Co layer 5 and the Fe layer 9 are a laminated film made of Ru layer 3 / Co layer 5 / Cu layer 7 and a laminated film made of Cu layer 7 / Fe layer 9 / Cu layer 13 prepared under the same conditions as the element production. Was measured by magnetization measurement and ferromagnetic resonance measurement. The magnetization of the Co layer 5 was 920 G, the magnitude of the anisotropic magnetic field perpendicular to the film surface was 3500 Oe, the magnetization of the Fe layer 9 was 1050 G, and the magnitude of the anisotropic magnetic field parallel to the film surface was 410 Oe. .

Ｃｏ層５の共鳴周波数は９．８ＧＨｚであり、Ｆｅ層９は膜面内にバイアス磁場を調整することにより共鳴周波数を９．５５ＧＨｚとした。オフ時の抵抗Ｒ０は１Ω、閾値電流は１．４μＡ、共鳴電圧ΔＶは０．１２ｍＶであり、オン時の実効抵抗は（ΔＶ／Ｉｔｈ）＋Ｒ０＝８７Ωである。この実施例の共鳴磁気抵抗効果素子に２μＡの電流を流した状態で外部磁場を印加するとＦｅ層９の共鳴周波数が変化するため図６に示したようにΔＶが変化し、磁気センサとして機能することがわかった。 The resonance frequency of the Co layer 5 is 9.8 GHz, and the Fe layer 9 has a resonance frequency of 9.55 GHz by adjusting a bias magnetic field in the film surface. The off-state resistance R 0 is 1Ω, the threshold current is 1.4 μA, the resonance voltage ΔV is 0.12 mV, and the on-state effective resistance is (ΔV / I th ) + R 0 = 87Ω. When an external magnetic field is applied to the resonant magnetoresistive effect element of this embodiment with a current of 2 μA flowing, the resonant frequency of the Fe layer 9 changes, so that ΔV changes as shown in FIG. 6 and functions as a magnetic sensor. I understood it.

（実施例２）
次に、本発明の実施例２による共鳴磁気抵抗効果素子の構成を図７に示す。図７は本実施例の共鳴磁気抵抗効果素子の構成を示す断面図である。本実施例の共鳴磁気抵抗効果素子は、実施例１の強磁性層５、非磁性層７、および強磁性層９の積層構造を２周期積層した構成となっている。本実施例の共鳴磁気抵抗効果素子は以下のように作製される。 (Example 2)
Next, FIG. 7 shows the configuration of a resonant magnetoresistive element according to Example 2 of the present invention. FIG. 7 is a cross-sectional view showing the configuration of the resonant magnetoresistive element of this example. The resonant magnetoresistive effect element of this example has a structure in which the laminated structure of the ferromagnetic layer 5, the nonmagnetic layer 7, and the ferromagnetic layer 9 of Example 1 is laminated for two periods. The resonant magnetoresistive element of the present example is manufactured as follows.

実施例１の場合と同様に、スパッタ成膜と電子線リソグラフィーを用いてサファイア基板１上に積層膜を形成した。この積層膜は、基板１から順にＲｕからなる非磁性層３、Ｃｏからなる強磁性層５１、Ｃｕからなる非磁性層７１、ＮｉＦｅからなる強磁性層９１、Ｃｕからなる非磁性層７、Ｃｏからなる強磁性層５２、Ｃｕからなる非磁性層７２、ＮｉＦｅからなる強磁性層９２、Ｃｕからなる非磁性層１３、Ｔａからなる非磁性層１５、およびＣｕからなる非磁性層１１を備えている。 As in the case of Example 1, a laminated film was formed on the sapphire substrate 1 using sputtering film formation and electron beam lithography. This laminated film includes a nonmagnetic layer 3 made of Ru in order from the substrate 1, a ferromagnetic layer 5 1 made of Co, a nonmagnetic layer 7 1 made of Cu, a ferromagnetic layer 9 1 made of NiFe, and a nonmagnetic layer made of Cu. 7, a ferromagnetic layer 5 2 made of Co, a nonmagnetic layer 7 2 made of Cu, a ferromagnetic layer 9 2 made of NiFe, a nonmagnetic layer 13 made of Cu, a nonmagnetic layer 15 made of Ta, and a nonmagnetic layer made of Cu A magnetic layer 11 is provided.

各層の厚さは、Ｒｕ層３が約１００ｎｍ、Ｃｏ層５１、５２が約１ｎｍ、Ｃｕ層７１、７、７２が約５ｎｍ、ＮｉＦｅ層９１、９２が約１ｎｍ、Ｃｕ層１３が約１０ｎｍ、Ｔａ層１５が約２０ｎｍ、Ｃｕ層１１が約１００ｎｍとした。素子サイズは約１００×１００ｎｍ２とし、層間絶縁膜にはＳｉＯ２を用いた。 The thickness of each layer, Ru layer 3 is about 100 nm, Co layer 5 1, 5 2 is about 1 nm, Cu layer 7 1, 7, 7 2 of about 5 nm, NiFe layer 9 1, 9 2 of about 1 nm, Cu layer 13 is about 10 nm, Ta layer 15 is about 20 nm, and Cu layer 11 is about 100 nm. The element size was about 100 × 100 nm 2 and SiO 2 was used for the interlayer insulating film.

Ｃｏ層５１、５２は磁化の向きが膜面に実質的に垂直な磁性膜であり、磁化の向きが膜面に実質的に平行な磁性膜であるＮｉＦｅ層９１、９２の形成は、約１０００Ｏｅの磁場を膜面に平行に印加しながら成膜することで磁気的一軸異方性を付与した。Ｃｏ層５１、５２およびＮｉＦｅ層９１、９２の磁気特性は素子作製と同一条件で作製したＲｕ層３／Ｃｏ層５１／Ｃｕ７１層の積層膜およびＣｕ層７１／ＮｉＦｅ層９１／Ｃｕ層７の積層膜の磁化測定および強磁性共鳴測定により調べた。Ｃｏ層５１の磁化は９２０Ｇ、膜面に垂直な異方性磁場の大きさは３５００Ｏｅであり、ＮｉＦｅ層９１の磁化は８１０Ｇ、面内異方性磁場の大きさは２２０Ｏｅであった。 The Co layers 5 1 and 5 2 are magnetic films whose magnetization direction is substantially perpendicular to the film surface, and the formation of NiFe layers 9 1 and 9 2 that are magnetic films whose magnetization direction is substantially parallel to the film surface. Gave a magnetic uniaxial anisotropy by applying a magnetic field of about 1000 Oe in parallel to the film surface. The magnetic properties of the Co layers 5 1 , 5 2 and the NiFe layers 9 1 , 9 2 are the same as those of the element fabrication: Ru layer 3 / Co layer 5 1 / Cu7 1 layer stack film and Cu layer 7 1 / NiFe layer It investigated by the magnetization measurement and the ferromagnetic resonance measurement of the laminated film of 9 1 / Cu layer 7. Magnetization of the Co layer 5 1 920G, the magnitude of the perpendicular anisotropy field to the film plane is 3500 Oe, the magnetization of the NiFe layer 9 1 810G, the magnitude of the in-plane anisotropy field was 220Oe.

Ｃｏ層５１、５２の共鳴周波数は９．８ＧＨｚであり、ＮｉＦｅ層９１、９２は膜面内にバイアス磁場を調整することにより共鳴周波数を９．６ＧＨｚとした。オフ時の抵抗Ｒ０は１．３Ω、閾値電流は１．８μＡ、共鳴電圧ΔＶは０．２１ｍＶであり、オン時の実効抵抗は（ΔＶ／Ｉｔｈ）＋Ｒ０＝１１８Ωとなり、積層数を増すことにより共鳴電圧を大きくすることができた。 Resonance frequency of the Co layer 5 1, 5 2 is 9.8 GHz, NiFe layer 9 1, 9 2 was 9.6GHz resonant frequency by adjusting a bias magnetic field to the film plane. The off-state resistance R 0 is 1.3Ω, the threshold current is 1.8 μA, the resonance voltage ΔV is 0.21 mV, and the on-state effective resistance is (ΔV / I th ) + R 0 = 118Ω, increasing the number of layers. As a result, the resonance voltage could be increased.

（実施例３）
実施例１と同様な方法で実施例１における厚さ１ｎｍのＦｅ層を厚さ１．２ ｎｍのＣｏ膜（面内磁化膜）で置き換えた以外は同様な構造の素子を作製した。磁化測定からこのＣｏ膜の形状異方性磁場４πＭｓと膜面に垂直方向の結晶異方性磁場ＨＡ１との差（４πＭｓ−ＨＡ１）は３５０Ｏｅであることが分かった。この素子に５００Ｏｅのバイアス磁場を膜面に垂直方向に印加し、厚さ１．２ｎｍのＣｏ層の磁化を膜面垂直にした状態で電流を流したところ、２μＡ以上で０．１５ｍＶの共鳴電圧が観測された。さらにバイアス磁場と逆向きに外部磁場を印加したところ３０Ｏｅの磁場印加により共鳴電圧が０．５ｍＶに減少することが観測されこの素子が膜面に垂直方向の磁場に対する磁気センサーとしても機能することが確認された。 (Example 3)
A device having the same structure was produced in the same manner as in Example 1, except that the 1 nm thick Fe layer in Example 1 was replaced with a 1.2 nm thick Co film (in-plane magnetic film). From the magnetization measurement, it was found that the difference (4πM s −H A1 ) between the shape anisotropy field 4πM s of this Co film and the crystal anisotropy field H A1 perpendicular to the film surface was 350 Oe. When a bias magnetic field of 500 Oe was applied to this element in a direction perpendicular to the film surface, and a current was passed with the magnetization of the Co layer having a thickness of 1.2 nm perpendicular to the film surface, a resonance voltage of 0.15 mV at 2 μA or more. Was observed. Furthermore, when an external magnetic field was applied in the direction opposite to the bias magnetic field, it was observed that the resonance voltage was reduced to 0.5 mV by applying a magnetic field of 30 Oe, and this element can also function as a magnetic sensor for a magnetic field perpendicular to the film surface. confirmed.

以上、本発明の実施の形態と実施例について説明したが、本発明はこれらに限られず、特許請求の範囲に記載の発明の要旨の範疇において様々に変更可能である。   Although the embodiments and examples of the present invention have been described above, the present invention is not limited to these, and various modifications can be made within the scope of the gist of the invention described in the claims.

また、本発明は、実施段階においてその要旨を逸脱しない範囲で種々に変形することが可能である。   In addition, the present invention can be variously modified without departing from the scope of the invention in the implementation stage.

以上述べたように、本実施例の共鳴磁気抵抗効果素子は、通常の成膜技術を用いて作製することができ、また素子の接合面積が減少しても感度およびＳＮ比が低減しないという特徴を有し、高密度と高い磁気抵抗変化を実現することができる。   As described above, the resonant magnetoresistive effect element of this embodiment can be manufactured by using a normal film forming technique, and the sensitivity and SN ratio are not reduced even if the junction area of the element is reduced. It is possible to realize high density and high magnetoresistance change.

本発明の第１実施形態による共鳴磁気抵抗効果素子を示す断面図。Sectional drawing which shows the resonant magnetoresistive effect element by 1st Embodiment of this invention. 強磁性体の磁化の熱ゆらぎのパワースペクトルを説明する図。The figure explaining the power spectrum of the thermal fluctuation of magnetization of a ferromagnetic. 第１実施形態による共鳴磁気抵抗効果素子の素子特性を示す図。The figure which shows the element characteristic of the resonant magnetoresistive effect element by 1st Embodiment. 本発明の第２実施形態による共鳴磁気抵抗効果素子を示す断面図。Sectional drawing which shows the resonant magnetoresistive effect element by 2nd Embodiment of this invention. 本発明の実施例１による共鳴磁気抵抗効果素子を示す断面図。Sectional drawing which shows the resonance magnetoresistive effect element by Example 1 of this invention. 実施例１による共鳴磁気抵抗効果素子の抵抗値が外部磁場に依存することを示す図。The figure which shows that the resistance value of the resonant magnetoresistive effect element by Example 1 depends on an external magnetic field. 本発明の実施例２による共鳴磁気抵抗効果素子を示す断面図。Sectional drawing which shows the resonant magnetoresistive effect element by Example 2 of this invention. 第１実施形態の変形例による共鳴磁気抵抗効果素子を示す断面図。Sectional drawing which shows the resonance magnetoresistive effect element by the modification of 1st Embodiment. 本発明の第３実施形態による共鳴磁気抵抗効果素子を示す断面図。Sectional drawing which shows the resonant magnetoresistive effect element by 3rd Embodiment of this invention. 第３実施形態の変形例による共鳴磁気抵抗効果素子を示す断面図。Sectional drawing which shows the resonance magnetoresistive effect element by the modification of 3rd Embodiment. 磁気記録再生装置の概略構成を示す要部斜視図。FIG. 2 is a perspective view of a main part showing a schematic configuration of a magnetic recording / reproducing apparatus. アクチュエータアームから先の磁気ヘッドアセンブリをディスク側から眺めた拡大斜視図。The enlarged perspective view which looked at the magnetic head assembly ahead from an actuator arm from the disk side.

符号の説明Explanation of symbols

１ 基板
３ 下部電極
５ 強磁性層
７ 非磁性層
９ 強磁性層
１１ 上部電極 1 Substrate 3 Lower electrode 5 Ferromagnetic layer 7 Nonmagnetic layer 9 Ferromagnetic layer 11 Upper electrode

Claims (13)

磁化の向きが膜面に平行な第１磁性層と、磁化の向きが膜面に垂直な単一の磁性体である第２磁性層と、前記第１および第２磁性層の間に設けられた第１非磁性層と、を有する積層膜が第２非磁性層を介して複数個積層された積層構造と、
前記積層構造の、積層方向の一方の端面側に設けられ前記一方の端面と電気的に接続する第１電極と、
前記積層構造の、積層方向の他方の端面側に設けられ前記他方の端面と電気的に接続する第２電極と、
前記積層構造と前記第１電極との間に設けられた垂直磁化バイアス膜と、
を備え、前記第２磁性層から前記第１磁性層に向かう方向に電流を流すことにより、前記第１磁性層のスピンゆらぎを前記第２磁性層に注入して前記第２磁性層に磁気共鳴を誘起することを特徴とする磁気センサ。 A first magnetic layer having a magnetization direction parallel to the film surface, a second magnetic layer that is a single magnetic body having a magnetization direction perpendicular to the film surface, and the first and second magnetic layers. A laminated structure in which a plurality of laminated films having the first nonmagnetic layer are laminated via the second nonmagnetic layer ;
A first electrode provided on one end face side in the stacking direction of the laminated structure and electrically connected to the one end face;
A second electrode provided on the other end face side in the stacking direction of the stacked structure and electrically connected to the other end face;
A perpendicular magnetization bias film provided between the stacked structure and the first electrode;
And applying a current in a direction from the second magnetic layer to the first magnetic layer, thereby injecting spin fluctuations of the first magnetic layer into the second magnetic layer to cause magnetic resonance in the second magnetic layer. Inductive magnetic sensor. 磁化の向きが膜面に平行な第１磁性層と、磁化の向きが膜面に垂直な単一の磁性体である第２磁性層と、前記第１および第２磁性層の間に設けられた第１非磁性層と、を有する積層膜が第２非磁性層を介して複数個積層された積層構造と、
前記積層構造の側部に設けられた水平磁化バイアス膜と、
を備え、前記第２磁性層から前記第１磁性層に向かう方向に電流を流すことにより、前記第１磁性層のスピンゆらぎを前記第２磁性層に注入して前記第２磁性層に磁気共鳴を誘起することを特徴とする磁気センサ。 A first magnetic layer having a magnetization direction parallel to the film surface, a second magnetic layer that is a single magnetic body having a magnetization direction perpendicular to the film surface, and the first and second magnetic layers. A laminated structure in which a plurality of laminated films having the first nonmagnetic layer are laminated via the second nonmagnetic layer;
A horizontal magnetization bias film provided on a side of the laminated structure ;
And applying a current in a direction from the second magnetic layer to the first magnetic layer, thereby injecting spin fluctuations of the first magnetic layer into the second magnetic layer to cause magnetic resonance in the second magnetic layer. Inductive magnetic sensor. 磁化の向きが膜面に平行な第１磁性層と、磁化の向きが膜面に垂直な単一の磁性体である第２磁性層と、前記第１および第２磁性層の間に設けられた第１非磁性層と、を有する積層膜が第２非磁性層を介して複数個積層された積層構造と、
前記積層構造の側部に設けられた垂直磁化バイアス膜と、
を備え、前記第２磁性層から前記第１磁性層に向かう方向に電流を流すことにより、前記第１磁性層のスピンゆらぎを前記第２磁性層に注入して前記第２磁性層に磁気共鳴を誘起することを特徴とする磁気センサ。 A first magnetic layer having a magnetization direction parallel to the film surface, a second magnetic layer that is a single magnetic body having a magnetization direction perpendicular to the film surface, and the first and second magnetic layers. A laminated structure in which a plurality of laminated films having the first nonmagnetic layer are laminated via the second nonmagnetic layer;
A perpendicular magnetization bias film provided on a side of the laminated structure ;
And applying a current in a direction from the second magnetic layer to the first magnetic layer, thereby injecting spin fluctuations of the first magnetic layer into the second magnetic layer to cause magnetic resonance in the second magnetic layer. Inductive magnetic sensor. 前記第１および第２磁性層はそれぞれ単層であることを特徴とする請求項１乃至３のいずれかに記載の磁気センサ。 The magnetic sensor according to any of claims 1 to 3, wherein the first and second magnetic layers are each monolayer. 前記第１磁性層における形状異方性磁場と膜面に垂直方向の結晶異方性磁場の大きさの差が５００Oe以下であることを特徴とする請求項１乃至４のいずれかに記載の磁気センサ。 Magnetic according to any one of claims 1 to 4, characterized in that the size difference of the crystal anisotropy field of the first shape anisotropy field in the magnetic layer and the film surface in the vertical direction is less 500Oe Sensor. 前記第２磁性層における形状異方性磁場と膜面に垂直方向の結晶異方性磁場の大きさの差が５００Oe以下であることを特徴とする請求項１乃至５のいずれかに記載の磁気センサ。 Magnetic according to any one of claims 1 to 5 size difference of the crystal anisotropy field of the second direction perpendicular to the shape anisotropy field and the film surface of the magnetic layer is equal to or less than 500Oe Sensor. 前記第１磁性層と前記第２磁性層の少なくても一方が単磁区構造であることを特徴とする請求項１乃至６のいずれかに記載の磁気センサ。 The magnetic sensor according to any of claims 1 to 6, characterized in that one be less of the second magnetic layer and the first magnetic layer has a single domain structure. 前記第１および第２磁性層の厚さがそれぞれ３ｎｍ以下であることを特徴とする請求項１乃至３のいずれかに記載の磁気センサ。 The magnetic sensor according to any one of claims 1 to 3, wherein the thickness of said first and second magnetic layer is 3nm or less, respectively. 前記請求項１乃至３のいずれかに記載の磁気センサを再生素子として搭載していることを特徴とする磁気ヘッド。 Magnetic head is characterized in that by mounting a magnetic sensor according as the reproduction device to any of claims 1 to 3. 請求項９記載の磁気ヘッドを備えていることを特徴とする磁気記録再生装置。   A magnetic recording / reproducing apparatus comprising the magnetic head according to claim 9. 磁化の向きが膜面に平行な第１および第２磁性層と、前記第１および第２磁性層間に設けられ、磁化の向きが膜面に垂直な単一の磁性体である第３磁性層および非磁性層が複数個積層された積層膜とを備え、前記第１および第２磁性層に電流を流すことにより、前記第１または第２磁性層のスピンゆらぎを前記第３磁性層に注入して前記第３磁性層に磁気共鳴を誘起することを特徴とする磁気センサ。   First and second magnetic layers whose magnetization direction is parallel to the film surface, and a third magnetic layer which is provided between the first and second magnetic layers and is a single magnetic body whose magnetization direction is perpendicular to the film surface And a laminated film in which a plurality of nonmagnetic layers are laminated, and by causing a current to flow through the first and second magnetic layers, the spin fluctuation of the first or second magnetic layer is injected into the third magnetic layer And magnetic resonance is induced in the third magnetic layer. 前記第１および第２磁性層と、前記第３磁性層との少なくても一方が単磁区構造であることを特徴とする請求項１１記載の磁気センサ。   12. The magnetic sensor according to claim 11, wherein at least one of the first and second magnetic layers and the third magnetic layer has a single magnetic domain structure. 前記第１乃至第３磁性層の厚さがそれぞれ３ｎｍ以下であることを特徴とする請求項１２記載の磁気センサ。   13. The magnetic sensor according to claim 12, wherein each of the first to third magnetic layers has a thickness of 3 nm or less.
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