JP3083090B2 - Magnetoresistive sensor - Google Patents
Magnetoresistive sensorInfo
- Publication number
- JP3083090B2 JP3083090B2 JP10302263A JP30226398A JP3083090B2 JP 3083090 B2 JP3083090 B2 JP 3083090B2 JP 10302263 A JP10302263 A JP 10302263A JP 30226398 A JP30226398 A JP 30226398A JP 3083090 B2 JP3083090 B2 JP 3083090B2
- Authority
- JP
- Japan
- Prior art keywords
- layer
- ferromagnetic layer
- magnetoresistive sensor
- ferromagnetic
- film
- 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.)
- Expired - Fee Related
Links
- 230000005294 ferromagnetic effect Effects 0.000 claims description 79
- 230000005291 magnetic effect Effects 0.000 claims description 58
- 230000005290 antiferromagnetic effect Effects 0.000 claims description 36
- 229910000480 nickel oxide Inorganic materials 0.000 claims description 25
- 230000005415 magnetization Effects 0.000 claims description 24
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 17
- 125000006850 spacer group Chemical group 0.000 claims description 17
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 claims description 11
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 8
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 7
- 229910045601 alloy Inorganic materials 0.000 claims description 4
- 239000000956 alloy Substances 0.000 claims description 4
- 230000004907 flux Effects 0.000 claims description 4
- 238000000034 method Methods 0.000 claims description 3
- 238000001514 detection method Methods 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 239000010410 layer Substances 0.000 description 164
- 230000035945 sensitivity Effects 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 229910000859 α-Fe Inorganic materials 0.000 description 6
- 230000008878 coupling Effects 0.000 description 4
- 238000010168 coupling process Methods 0.000 description 4
- 238000005859 coupling reaction Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- 230000001939 inductive effect Effects 0.000 description 3
- 239000002356 single layer Substances 0.000 description 3
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 239000002885 antiferromagnetic material Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000011241 protective layer Substances 0.000 description 2
- 229910020707 Co—Pt Inorganic materials 0.000 description 1
- 229910003271 Ni-Fe Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 238000000992 sputter etching Methods 0.000 description 1
Landscapes
- Magnetic Heads (AREA)
- Hall/Mr Elements (AREA)
Description
【0001】[0001]
【発明の属する技術分野】本発明は、磁気的に記録され
た情報を再生する磁気抵抗センサ、特に、磁気ディスク
装置、磁気テープ装置に搭載される磁気ヘッドの再生素
子に関するものである。The present invention relates to a magnetoresistive sensor for reproducing magnetically recorded information, and more particularly to a reproducing element of a magnetic head mounted on a magnetic disk device and a magnetic tape device.
【0002】[0002]
【従来の技術】磁気記録再生装置、特に、磁気ディスク
装置における記録密度の向上は著しく、磁気ディスクの
キー・デバイスである再生用磁気ヘッドには高感度化が
要求されている。近年では、再生素子として磁気抵抗セ
ンサを利用したMRヘッドが用いられている。2. Description of the Related Art The recording density of a magnetic recording / reproducing apparatus, especially a magnetic disk apparatus, has been remarkably improved, and a high sensitivity is required for a reproducing magnetic head which is a key device of a magnetic disk. In recent years, an MR head using a magnetoresistive sensor has been used as a reproducing element.
【0003】MRヘッドは、従来のいわゆる誘導型ヘッ
ドに比べて、高い信号/ノイズ比(S/N比)が得られ
るのが特徴である。[0003] The MR head is characterized in that a higher signal / noise ratio (S / N ratio) can be obtained as compared with a conventional so-called inductive head.
【0004】現在のMRヘッドは、異方性磁気抵抗効果
(AMR効果)により、磁気ディスク上の磁気的な信号
を電気信号に変換しているが、AMR効果をもってして
もトラック幅、ビット長の狭小化が進行すると感度不足
になり、数Gb/in2程度が限界と考えられている。
これ以上の記録密度に対応するためには、より高感度の
磁気抵抗センサが必要であり、巨大磁気抵抗効果(GM
R効果)を用いたMRヘッドが注目されている。In the current MR head, a magnetic signal on a magnetic disk is converted into an electric signal by an anisotropic magnetoresistance effect (AMR effect). The sensitivity becomes insufficient as the narrowing progresses, and it is considered that the limit is about several Gb / in 2 .
In order to cope with higher recording densities, a more sensitive magnetoresistive sensor is required, and a giant magnetoresistive effect (GM
An MR head using the (R effect) has attracted attention.
【0005】GMR効果を用いたヘッドの一つとして、
特開平4−358310号公報には、スピンバルブ構造
と呼ばれる構造のものが示されている。これは、反強磁
性層によって磁化が特定の方向に固定された固定層と、
薄い非磁性導電層を介して固定層に積層された自由層で
構成されており、固定層の磁化と自由層の磁化の相対的
な角度によって、電気抵抗が変化するものである。As one of the heads using the GMR effect,
Japanese Patent Application Laid-Open No. 4-358310 discloses a structure called a spin valve structure. This is a fixed layer in which the magnetization is fixed in a specific direction by an antiferromagnetic layer,
It is composed of a free layer laminated on a fixed layer via a thin non-magnetic conductive layer, and its electric resistance changes depending on the relative angle between the magnetization of the fixed layer and the magnetization of the free layer.
【0006】上記公報では、反強磁性層としてFe50M
n50を用いているが、Fe50Mn50は耐食性が悪く、導
電性であるためにセンス電流がFe50Mn50にも分流し
て出力が減少すると云う問題がある。In the above publication, Fe 50 M is used as the antiferromagnetic layer.
Although n 50 is used, Fe 50 Mn 50 has poor corrosion resistance and has a problem that the sense current is shunted to Fe 50 Mn 50 and the output is reduced because of its conductivity.
【0007】このため、特開平5−347013号公報
にはFe50Mn50の替わりに酸化ニッケル(NiO)を
用いたスピンバルブセンサが、また、アイイーイーイー
トランザクション オン マグネティクス 34巻,
4号 954〜956頁には酸化ニッケル(NiO)と
酸化鉄(α−Fe2O3)の二層反強磁性体を用いたスピ
ンバルブセンサが記載されている。For this reason, Japanese Patent Application Laid-Open No. 5-347003 discloses a spin valve sensor using nickel oxide (NiO) instead of Fe 50 Mn 50 , and IEE Transaction on Magnetics, Vol.
No. 4, pages 954 to 956, a spin valve sensor using a two-layer antiferromagnetic material of nickel oxide (NiO) and iron oxide (α-Fe 2 O 3 ) is described.
【0008】反強磁性層として酸化ニッケル(NiO)
を用いた場合には、固定層である強磁性層との交換結合
特性は、図6に示すように、一方向異方性磁界(Hu
a)よりも固定層の保磁力(Hcp)の方が大きく、何
らかの大きな外部磁界が加わったときには、ゼロ磁界近
傍における磁化の状態が変わり感度が低下してしまう。[0008] Nickel oxide (NiO) as an antiferromagnetic layer
In the case where is used, as shown in FIG. 6, the exchange coupling characteristic with the ferromagnetic layer as the fixed layer is a unidirectional anisotropic magnetic field (Hu).
The coercive force (Hcp) of the fixed layer is higher than that of a), and when any large external magnetic field is applied, the magnetization state near the zero magnetic field changes and the sensitivity decreases.
【0009】これを改善する方法として、特開平7−1
69026号公報には、固定層を強磁性層/非磁性スペ
ーサ層/強磁性層と云う積層構造にすることが提案され
ており、さらに、特開平9−16920号公報には酸化
ニッケル(Ni1-xCoxO)などの反強磁性層の上に、
強磁性層/非磁性スペーサ層/強磁性層を積層した構造
が開示されている。As a method for improving this, Japanese Patent Application Laid-Open No. 7-1
The 69026 discloses the fixed layer and it is proposed to the laminate structure referred to as a ferromagnetic layer / a nonmagnetic spacer layer / ferromagnetic layer, further, Japanese Patent Laid-Open No. 9-16920 nickel oxide (Ni 1 -x Co x O)
A structure in which a ferromagnetic layer / a nonmagnetic spacer layer / a ferromagnetic layer is stacked is disclosed.
【0010】[0010]
【発明が解決しようとする課題】特開平5−34701
3号公報では、酸化ニッケル(NiO)を用いたスピン
バルブセンサが、アイイーイーイー トランザクション
オン マグネティクス34巻,4号 954〜956
頁には、酸化ニッケル(NiO)と酸化鉄(α−Fe2
O3)の二層反強磁性体を用いたスピンバルブセンサが
示されているが、固定層との交換結合特性、特に、Hu
aが十分大きいとは云えず、外部磁界に対する安定性が
懸念される。Problems to be Solved by the Invention Japanese Patent Laid-Open No. 5-34701
In Japanese Patent Publication No. 3 (1993), a spin valve sensor using nickel oxide (NiO) is disclosed in IEE Transaction on Magnetics Vol. 34, No. 4, 954-956.
The page shows nickel oxide (NiO) and iron oxide (α-Fe 2
Although a spin valve sensor using a two-layer antiferromagnetic material of O 3 ) is shown, exchange coupling characteristics with a fixed layer, particularly Hu
a cannot be said to be sufficiently large, and there is a concern about stability against an external magnetic field.
【0011】特開平9−16920号公報では、酸化ニ
ッケル(Ni1-xCoxO)などの反強磁性層の上に、強
磁性層/非磁性スペーサ層/強磁性層からなる固定層を
積層することにより、見かけ上Huaが大きくなり、外
部磁界に対する安定性が向上することが示されている。In Japanese Patent Application Laid-Open No. Hei 9-16920, a fixed layer composed of a ferromagnetic layer / a nonmagnetic spacer layer / a ferromagnetic layer is provided on an antiferromagnetic layer such as nickel oxide (Ni 1-x Co x O). It is shown that the lamination increases the apparent Hua and improves the stability against an external magnetic field.
【0012】この構造では、酸化ニッケル反強磁性層
と、これに接する強磁性層との間の交換結合特性が、外
部磁界に対する安定性を決定する要因の一つになってい
る。酸化ニッケルと強磁性層の交換結合特性は、Hua
よりもHcpの方が大きく、ある程度の大きさの外部磁
界が作用した場合には、磁界ゼロ近傍で磁化状態が変わ
ってしまう可能性がある。この問題は、固定層を強磁性
層/非磁性スペーサ層/強磁性層にしても、磁界ゼロ近
傍での磁化状態が変化しない外部磁界の大きさが大きく
なるだけで、本質的には解決することはできない。In this structure, the exchange coupling characteristic between the nickel oxide antiferromagnetic layer and the ferromagnetic layer in contact with it is one of the factors that determine the stability to an external magnetic field. The exchange coupling characteristic between nickel oxide and the ferromagnetic layer is Hua.
Hcp is larger than Hcp, and when an external magnetic field of a certain magnitude acts, the magnetization state may change near zero magnetic field. This problem is essentially solved even if the pinned layer is made of a ferromagnetic layer / non-magnetic spacer layer / ferromagnetic layer, only the magnitude of the external magnetic field whose magnetization state does not change near zero magnetic field increases. It is not possible.
【0013】本発明の目的は、外部磁界に対して安定
で、高感度、高出力を有する磁気抵抗センサを提供する
ことにある。An object of the present invention is to provide a magnetoresistive sensor which is stable to an external magnetic field, has high sensitivity, and has high output.
【0014】[0014]
【課題を解決するための手段】上記目的を達成する本発
明の要旨は次のとおりである。The gist of the present invention to achieve the above object is as follows.
【0015】〔1〕 非磁性導電層を介して第1の強磁
性層と第2の強磁性層が積層され、非磁性スペーサ層を
介して前記第2の強磁性層と第3の強磁性層が積層され
ており、前記第2の強磁性層と前記第3の強磁性層が非
磁性スペーサ層を介して反強磁性的に結合しており、前
記第1の強磁性層の磁化の方向が外部磁界ゼロのときに
前記第2の強磁性層の磁化の方向とある角度を成し、前
記第1の強磁性層の磁化の方向と前記第2の強磁性層の
磁化の方向の相対的な角度が変わることによって電気抵
抗が変化する磁気抵抗センサ膜と、前記磁気抵抗センサ
膜に信号検出電流を流すための電極と、前記磁気抵抗セ
ンサ膜の電気抵抗変化を検知する手段を有する磁気抵抗
センサにおいて、前記第3の強磁性層が酸化鉄FexO
(但し、0.57≦x≦0.70)からなる第1の反強磁
性層の上に積層されており、前記第1の反強磁性層が酸
化ニッケル(Ni1-xCox)O(但し、0≦x≦0.
5)からなる第2の反強磁性層の上に積層されており、
前記第3の強磁性層の飽和磁束密度と膜厚の積が、前記
第2の強磁性層の飽和磁束密度と膜厚の積よりも小さい
ことを特徴とする磁気抵抗センサ。[1] A first ferromagnetic layer and a second ferromagnetic layer are stacked with a nonmagnetic conductive layer interposed therebetween, and the second ferromagnetic layer and the third ferromagnetic layer are stacked with a nonmagnetic spacer layer interposed therebetween. Layers are stacked, the second ferromagnetic layer and the third ferromagnetic layer are antiferromagnetically coupled via a non-magnetic spacer layer, and the magnetization of the first ferromagnetic layer is The direction forms an angle with the direction of magnetization of the second ferromagnetic layer when the external magnetic field is zero, and the direction of the magnetization of the first ferromagnetic layer and the direction of magnetization of the second ferromagnetic layer are different. A magnetoresistive sensor film whose electric resistance changes due to a change in relative angle; an electrode for flowing a signal detection current through the magnetoresistive sensor film; and a means for detecting a change in electric resistance of the magnetoresistive sensor film In the magnetoresistive sensor, the third ferromagnetic layer is formed of iron oxide Fe x O
(Where 0.57 ≦ x ≦ 0.70), wherein the first antiferromagnetic layer is formed of nickel oxide (Ni 1-x Co x ) O. (However, 0 ≦ x ≦ 0.
5) being laminated on the second antiferromagnetic layer comprising
The product of the saturation magnetic flux density and the film thickness of the third ferromagnetic layer is
A magnetoresistive sensor characterized by being smaller than the product of the saturation magnetic flux density and the thickness of the second ferromagnetic layer .
【0016】〔2〕 前記第2の反強磁性層の膜厚が3
0nm以上である前記の磁気抵抗センサ。[2] The thickness of the second antiferromagnetic layer is 3
The aforementioned magnetoresistive sensor having a thickness of 0 nm or more.
【0017】〔3〕 前記第1の反強磁性層の膜厚が
0.5〜10nmである前記の磁気抵抗センサ。[3] The magnetoresistive sensor as described above, wherein the thickness of the first antiferromagnetic layer is 0.5 to 10 nm.
【0018】〔4〕 前記第3の強磁性層がFe,C
o,Niおよびそれらの合金である前記の磁気抵抗セン
サ。[4] The third ferromagnetic layer is made of Fe, C
The magnetoresistive sensor as described above, which is o, Ni or an alloy thereof.
【0019】〔5〕 前記第3の強磁性層がCo1-xF
ex(但し、0<x≦0.2)である前記〔4〕に記載の
磁気抵抗センサ。[5] The third ferromagnetic layer is made of Co 1-x F
e x (where, 0 <x ≦ 0.2) magnetoresistive sensor according to the a [4].
【0020】[0020]
【発明の実施の形態】以下、本発明による実施の形態に
ついて、図面を用いて説明する。まず、本発明の磁気抵
抗センサ膜の構成を図1に示す。Embodiments of the present invention will be described below with reference to the drawings. First, the configuration of the magnetoresistive sensor film of the present invention is shown in FIG.
【0021】Si基板10の上に、第2の反強磁性層1
11としてNiO50nm、第1の反強磁性層112と
してα−Fe2O32nmを積層して反強磁性層11を形
成した。その上に第3の強磁性層12、非磁性スペーサ
層13としてRu0.8nm、第2の強磁性層14,非
磁性導電層15としてCu2.5nm、第1の強磁性層
16としてCo1nmとNiFe5nmの2層膜、さら
に保護層17としてTa5nmを順次積層した。On the Si substrate 10, the second antiferromagnetic layer 1
NiO50nm as 11, to form the antiferromagnetic layer 11 by laminating a α-Fe 2 O 3 2nm as the first antiferromagnetic layer 112. On top of this, the third ferromagnetic layer 12, the non-magnetic spacer layer 13 are Ru 0.8 nm, the second ferromagnetic layer 14 and the non-magnetic conductive layer 15 are Cu 2.5 nm, and the first ferromagnetic layer 16 is Co1 nm and NiFe 5 nm. And a protective layer 17 of Ta5 nm was sequentially laminated.
【0022】なお、第3の強磁性層12/非磁性スペー
サ層13/第2の強磁性層14が固定層に、第1の強磁
性層16が自由層に相当する。The third ferromagnetic layer 12 / nonmagnetic spacer layer 13 / second ferromagnetic layer 14 corresponds to a fixed layer, and the first ferromagnetic layer 16 corresponds to a free layer.
【0023】ここで、第3の強磁性層12、第2の強磁
性層14にはCo90Fe10を用い、それぞれの膜厚を
2.5nmと3.0nmとした。なお、第3および第2の
強磁性層の磁化が、それぞれ102および101の方向
に異方性が誘導されるよう、第1の強磁性層については
100の方向に誘導されるように、成膜時に基板面とほ
ぼ平行に磁界を印加した。Here, Co 90 Fe 10 was used for the third ferromagnetic layer 12 and the second ferromagnetic layer 14, and their thicknesses were set to 2.5 nm and 3.0 nm, respectively. The magnetizations of the third and second ferromagnetic layers are formed such that anisotropy is induced in directions 102 and 101, respectively, and that the first ferromagnetic layer is induced in direction 100. During the film formation, a magnetic field was applied substantially parallel to the substrate surface.
【0024】磁気抵抗センサ膜成膜後、101に示す方
向に15kOeの磁界を印加しながら、230℃、3時
間の熱処理を行い、反強磁性層11と第3の強磁性層1
2との間に一方向異方性を発生させた。この熱処理によ
り、自由層、即ち、第1の強磁性層16の磁化の方向も
101の方向を向く。After forming the magnetoresistive sensor film, a heat treatment is performed at 230 ° C. for 3 hours while applying a magnetic field of 15 kOe in the direction indicated by 101 to obtain the antiferromagnetic layer 11 and the third ferromagnetic layer 1.
A unidirectional anisotropy was generated between the two. By this heat treatment, the direction of magnetization of the free layer, that is, the first ferromagnetic layer 16 is also directed to the direction of 101.
【0025】上記のように作製した磁気抵抗センサ膜の
磁気抵抗変化曲線を測定した。比較のため、第3の強磁
性層12/非磁性スペーサ層13/第2の強磁性層14
からなる固定層で、反強磁性層11がNiO50nm単
層で構成されているもの、さらに図2に示すように、固
定層がCo90Fe103.0nmからなる第2の強磁性層
14のみで構成されており、反強磁性層11が第2の反
強磁性層111であるNiO50nmと、第1の反強磁
性層112であるα−Fe2O32nmの積層膜で構成さ
れているものと、反強磁性層11がNiO50nmのみ
で構成されているものも作製し、特性を比較した。The magnetoresistance change curve of the magnetoresistive sensor film produced as described above was measured. For comparison, the third ferromagnetic layer 12 / nonmagnetic spacer layer 13 / second ferromagnetic layer 14
The antiferromagnetic layer 11 is composed of a single layer of 50 nm of NiO, and as shown in FIG. 2, only the second ferromagnetic layer 14 of which the fixed layer is composed of 3.0 nm of Co 90 Fe 10 The antiferromagnetic layer 11 is composed of a laminated film of 50 nm of NiO as the second antiferromagnetic layer 111 and 2 nm of α-Fe 2 O 3 as the first antiferromagnetic layer 112. A sample and a sample in which the antiferromagnetic layer 11 is composed of only 50 nm of NiO were also prepared, and their characteristics were compared.
【0026】図3および図4は、固定層が第3の強磁性
層12/非磁性スペーサ層13/第2の強磁性層14か
らなる積層構造で、反強磁性層がそれぞれNiO50n
mとα−Fe2O32nmの積層膜、および、NiO50
nm単層である磁気抵抗センサ膜について、±2kOe
の磁界を印加して測定した磁気抵抗変化曲線である。FIGS. 3 and 4 show a laminated structure in which the fixed layer is composed of the third ferromagnetic layer 12 / non-magnetic spacer layer 13 / second ferromagnetic layer 14, and the antiferromagnetic layers are each composed of NiO50n.
m and α-Fe 2 O 3 2 nm laminated film and NiO 50
± 2 kOe for a magnetoresistive sensor film that is a single nm
4 is a magnetoresistance change curve measured by applying a magnetic field of FIG.
【0027】また、図5および図6は、固定層が第2の
強磁性層14のみからなり、反強磁性層がそれぞれNi
O50nmとα−Fe2O32nmの積層膜、および、N
iO50nm単層である磁気抵抗センサ膜について、±
1.5kOeの磁界を印加して測定した磁気抵抗変化曲
線である。FIGS. 5 and 6 show that the fixed layer is composed of only the second ferromagnetic layer 14 and the antiferromagnetic layer is composed of Ni.
O 50 nm and α-Fe 2 O 3 2 nm laminated film, and N
Regarding the magnetoresistive sensor film having a single layer of iO50 nm, ±
It is a magnetoresistance change curve measured by applying a magnetic field of 1.5 kOe.
【0028】固定層が第2の強磁性層14のみである場
合には、図5および図6より、それぞれ1300Oe、
1100Oeの磁界を印加すると、ゼロ磁界近傍におけ
る磁化状態が変わり、ΔRが低下することが分かる。When the fixed layer is the second ferromagnetic layer 14 only, as shown in FIGS. 5 and 6, 1300 Oe,
It can be seen that when a magnetic field of 1100 Oe is applied, the magnetization state near the zero magnetic field changes, and ΔR decreases.
【0029】一方、固定層として第3の強磁性層12/
非磁性スペーサ層13/第2の強磁性層14の積層構造
を用いると、図4に示すようにNiO反強磁性層単層で
ある場合にもゼロ磁界近傍における磁化状態の変化は小
さくなるが、完全にはなくすことはできない。On the other hand, the third ferromagnetic layer 12 /
When the laminated structure of the nonmagnetic spacer layer 13 / the second ferromagnetic layer 14 is used, the change in the magnetization state near zero magnetic field is small even in the case of a single NiO antiferromagnetic layer as shown in FIG. Cannot be completely eliminated.
【0030】ここで、反強磁性層としてNiOとα−F
e2O3の積層膜を用いると、図3のようにゼロ磁界近傍
での磁化状態の変化は観測されず、外部磁界に対して安
定であることが分かる。Here, NiO and α-F are used as the antiferromagnetic layer.
If a laminated film of e 2 O 3, a change in magnetization state of zero magnetic field near as in Figure 3 is not observed, it can be seen that is stable to the external magnetic field.
【0031】図3のような外部磁界に対して安定な応答
は、第2の反強磁性層であるNiO反強磁性層の膜厚が
30nm以上、第1の反強磁性層であるα−Fe2O3の
膜厚が0.5〜10nmの範囲で得られた。また、α−
Fe2O3の組成は必ずしも化学量論組成である必要はな
く、FexOと表したときに0.57≦x≦0.70の範
囲にあればよい。A stable response to an external magnetic field as shown in FIG. 3 is obtained when the thickness of the NiO antiferromagnetic layer as the second antiferromagnetic layer is 30 nm or more and the α- The thickness of Fe 2 O 3 was obtained in the range of 0.5 to 10 nm. Also, α-
The composition of Fe 2 O 3 is not necessarily a stoichiometric composition, it may be in the range of 0.57 ≦ x ≦ 0.70 when expressed as Fe x O.
【0032】次に、上記のような特性を有する磁気抵抗
センサ膜を、磁気抵抗効果型ヘッドに適用した実施の形
態について説明する。Next, an embodiment in which the magnetoresistive sensor film having the above characteristics is applied to a magnetoresistive head will be described.
【0033】図7は、本発明の第1の実施形態の磁気抵
抗効果型ヘッドの浮上面における構造を示す模式断面図
である。FIG. 7 is a schematic sectional view showing the structure of the air bearing surface of the magnetoresistive head according to the first embodiment of the present invention.
【0034】セラミクスからなる非磁性基板(図示省
略)の上に、アルミナ絶縁膜(図示省略)を約10μm
形成し、表面に精密研磨を施す。An alumina insulating film (not shown) is about 10 μm thick on a non-magnetic substrate (not shown) made of ceramics.
Formed and precision polished on the surface.
【0035】下部シールド層32として、めっき法によ
りNi−Fe系合金を約2μm形成し、イオンミリング
により所定の形状に加工する。下部ギャップ層33とし
てアルミナ膜を0.1μm成膜した後、磁気抵抗センサ
膜を形成する。反強磁性層41として第2の反強磁性層
411(NiO50nm)と、第1の反強磁性層412
(α−Fe2O32nm)とを積層した後、第3の強磁性
層42としてCo90Fe10を2.5nm、非磁性スペー
サ層43としてRuを0.8nm、第2の強磁性層44
としてCo90Fe10を3.0nm成膜した。これらの3
層が固定層である。As the lower shield layer 32, a Ni—Fe alloy is formed to a thickness of about 2 μm by a plating method, and is processed into a predetermined shape by ion milling. After forming an alumina film of 0.1 μm as the lower gap layer 33, a magnetoresistive sensor film is formed. A second antiferromagnetic layer 411 (NiO 50 nm) as the antiferromagnetic layer 41 and a first antiferromagnetic layer 412
(Α-Fe 2 O 3 2 nm), 2.5 nm of Co 90 Fe 10 as the third ferromagnetic layer 42, 0.8 nm of Ru as the nonmagnetic spacer layer 43, and the second ferromagnetic layer 44
Was formed as a film of Co 90 Fe 10 having a thickness of 3.0 nm. These three
The layer is a fixed layer.
【0036】その上に、非磁性導電層45であるCuを
2.5nm、第1の強磁性層(自由層)46であるCo
1nmとNiFe5nmの2層膜、保護層47であるT
a5nmを積層した。その後、磁気抵抗センサの素子高
さ方向に15kOeの磁界を印加しながら、250℃、
3時間熱処理を施した。On top of this, 2.5 nm of Cu as the nonmagnetic conductive layer 45 and Co as the first ferromagnetic layer (free layer) 46 are formed.
T layer which is a two-layer film of 1 nm and NiFe
a5 nm was laminated. Then, while applying a magnetic field of 15 kOe in the element height direction of the magnetoresistive sensor,
Heat treatment was performed for 3 hours.
【0037】この磁気抵抗センサ膜上にリフトオフマス
ク材を形成し、所定の形状に加工した後、その両端に、
硬磁性層34としてCo−Pt系合金膜、電極膜35と
してTaWとTaの積層膜を成膜した。A lift-off mask material is formed on the magnetoresistive sensor film and processed into a predetermined shape.
A Co—Pt alloy film was formed as the hard magnetic layer 34, and a laminated film of TaW and Ta was formed as the electrode film 35.
【0038】次いで、リフトオフマスク材を除去し、上
部ギャップ層(図示省略)、上部シールド層(図示省
略)を順次形成し、その上に記録用の誘導型磁気ヘッド
を形成するが、その詳細は省略する。Next, the lift-off mask material is removed, an upper gap layer (not shown) and an upper shield layer (not shown) are sequentially formed, and an inductive magnetic head for recording is formed thereon. Omitted.
【0039】誘導型磁気ヘッドの形成後、磁気抵抗セン
サの素子幅方向に300Oeの磁界を印加しながら、2
50℃、3時間熱処理を行い、第2および第3の強磁性
層の磁化の方向を概ね素子高さ方向に保ったまま、第1
の強磁性層(自由層)の磁化の方向を素子幅方向に向け
た。After forming the inductive magnetic head, while applying a magnetic field of 300 Oe in the element width direction of the magnetoresistive sensor,
A heat treatment is performed at 50 ° C. for 3 hours, and the first and the second ferromagnetic layers are kept in the direction of the element height while maintaining the magnetization directions in the first ferromagnetic layer.
The direction of magnetization of the ferromagnetic layer (free layer) was oriented in the element width direction.
【0040】上記のようにして作製した磁気抵抗効果型
ヘッドの再生出力、および、非対称性の変動率を書き込
み動作を行いながら評価した。ここで変動率は、書き込
み動作を行っていない状態での初期の出力および非対称
性の値に対する、それぞれの最大の変動分の割合と定め
た。The reproduction output and the asymmetry fluctuation rate of the magnetoresistive head manufactured as described above were evaluated while performing the writing operation. Here, the fluctuation rate is defined as the ratio of the maximum fluctuation to the initial output and the value of the asymmetry in a state where the writing operation is not performed.
【0041】固定層が第2の強磁性層14のみである磁
気抵抗効果型ヘッドや、固定層が第3の強磁性層12/
非磁性スペーサ層13/第2の強磁性層14の積層構造
であっても、反強磁性層がNiO単層である磁気抵抗効
果型ヘッドの再生出力および非対称性の変動率が10%
以上であるのに対し、本発明の磁気抵抗効果型ヘッドで
はいずれも2%以下と良好な結果が得られた。A magnetoresistive head in which the fixed layer is only the second ferromagnetic layer 14, or the fixed layer is the third ferromagnetic layer 12 /
Even in the laminated structure of the nonmagnetic spacer layer 13 / the second ferromagnetic layer 14, the variation in reproduction output and asymmetry of the magnetoresistive head in which the antiferromagnetic layer is a single NiO layer is 10%.
On the contrary, in the magnetoresistive head of the present invention, good results were obtained with 2% or less.
【0042】図8は、本発明の第2の実施形態の磁気抵
抗効果型ヘッドの浮上面における構造を示す模式断面図
である。FIG. 8 is a schematic cross-sectional view showing the structure of the air bearing surface of the magnetoresistive head according to the second embodiment of the present invention.
【0043】図8の構造は、図7の構造とほぼ同様であ
るが、電極膜35が硬磁性層34に対して、相対的に磁
気抵抗センサ膜のより内側まで入り込んだ構造となって
いる。この構造では、硬磁性層34からの磁界により、
実効的に感度が悪くなっている部分の影響を除くことが
できるので、電極膜35の間隔が狭いときに感度を向上
させることができる。The structure shown in FIG. 8 is substantially the same as the structure shown in FIG. 7, except that the electrode film 35 penetrates deeper into the magnetoresistive sensor film than the hard magnetic layer 34. . In this structure, the magnetic field from the hard magnetic layer 34 causes
Since the effect of the portion where the sensitivity is effectively deteriorated can be eliminated, the sensitivity can be improved when the interval between the electrode films 35 is narrow.
【0044】[0044]
【発明の効果】本発明によれば、外部磁界に対して安定
で、高感度、高出力を有する磁気抵抗センサを得ること
ができる。According to the present invention, it is possible to obtain a magnetoresistive sensor which is stable against an external magnetic field, has high sensitivity and high output.
【図1】本発明の磁気抵抗センサ膜の構成を示す模式断
面図である。FIG. 1 is a schematic sectional view showing a configuration of a magnetoresistive sensor film of the present invention.
【図2】固定層が一層の強磁性層からなる従来の磁気抵
抗センサ膜の構成を示す模式断面図である。FIG. 2 is a schematic cross-sectional view illustrating a configuration of a conventional magnetoresistive sensor film in which a fixed layer includes a single ferromagnetic layer.
【図3】本発明の磁気抵抗センサ膜の磁気抵抗変化曲線
を示すグラフである。FIG. 3 is a graph showing a magnetoresistance change curve of the magnetoresistance sensor film of the present invention.
【図4】固定層が強磁性層/非磁性スペーサ層/強磁性
層からなる従来の磁気抵抗センサ膜の磁気抵抗変化曲線
を示すグラフである。FIG. 4 is a graph showing a magnetoresistive change curve of a conventional magnetoresistive sensor film in which a fixed layer includes a ferromagnetic layer / a nonmagnetic spacer layer / a ferromagnetic layer.
【図5】固定層が一層の強磁性層からなり、反強磁性層
が積層構造である従来の磁気抵抗センサ膜の磁気抵抗変
化曲線を示すグラフである。FIG. 5 is a graph showing a magnetoresistive change curve of a conventional magnetoresistive sensor film in which a fixed layer includes one ferromagnetic layer and an antiferromagnetic layer has a laminated structure.
【図6】固定層が一層の強磁性層からなり、反強磁性層
が単層構造である従来の磁気抵抗センサ膜の磁気抵抗変
化曲線を示すグラフである。FIG. 6 is a graph showing a magnetoresistive change curve of a conventional magnetoresistive sensor film in which a fixed layer includes one ferromagnetic layer and an antiferromagnetic layer has a single-layer structure.
【図7】本発明の第1の実施の形態の磁気抵抗効果型ヘ
ッドの浮上面における構造を示す模式断面図である。FIG. 7 is a schematic cross-sectional view showing a structure on the air bearing surface of the magnetoresistive head according to the first embodiment of the present invention.
【図8】本発明の第2の実施の形態の磁気抵抗効果型ヘ
ッドの浮上面における構造を示す模式断面図である。FIG. 8 is a schematic cross-sectional view showing a structure on a flying surface of a magnetoresistive head according to a second embodiment of the present invention.
10…Si基板、11,41…反強磁性層、111,4
11…第2の反強磁性層、112,412…第1の反強
磁性層、12,42…第3の強磁性層、13,43…非
磁性スペーサ層、14,44…第2の強磁性層、15,
45…非磁性導電層、16,46…第1の強磁性層、1
7,47…保護層、100…第1の強磁性層の磁化の方
向、101…第2の強磁性層の磁化の方向、102…第
3の強磁性層の磁化の方向、32…下部シールド層、3
3…下部ギャップ層、34…硬磁性層、35…電極膜。10: Si substrate, 11, 41: antiferromagnetic layer, 111, 4
11: second antiferromagnetic layer, 112, 412: first antiferromagnetic layer, 12, 42: third ferromagnetic layer, 13, 43: nonmagnetic spacer layer, 14, 44: second strong Magnetic layer, 15,
45: non-magnetic conductive layer, 16, 46: first ferromagnetic layer, 1
7, 47: protective layer, 100: direction of magnetization of first ferromagnetic layer, 101: direction of magnetization of second ferromagnetic layer, 102: direction of magnetization of third ferromagnetic layer, 32: lower shield Layer, 3
3: Lower gap layer, 34: Hard magnetic layer, 35: Electrode film.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平11−168250(JP,A) 特開 平9−16920(JP,A) IEEE TRANSACTIONS MAGNETICS,Vol.34,N o.4,July 1998,pp.954− 956 (58)調査した分野(Int.Cl.7,DB名) H01L 43/00 - 43/14 H01F 10/08 G11B 5/39 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-11-168250 (JP, A) JP-A-9-16920 (JP, A) IEEE TRANSACTIONS MAGNETICS, Vol. 34, No. 4, July 1998, pp. 139-143. 954-956 (58) Fields surveyed (Int.Cl. 7 , DB name) H01L 43/00-43/14 H01F 10/08 G11B 5/39
Claims (3)
第2の強磁性層が積層され、非磁性スペーサ層を介して
前記第2の強磁性層と第3の強磁性層が積層されてお
り、前記第2の強磁性層と前記第3の強磁性層が非磁性
スペーサ層を介して反強磁性的に結合しており、前記第
1の強磁性層の磁化の方向が外部磁界ゼロのときに前記
第2の強磁性層の磁化の方向とある角度を成し、前記第
1の強磁性層の磁化の方向と前記第2の強磁性層の磁化
の方向の相対的な角度が変わることによって電気抵抗が
変化する磁気抵抗センサ膜と、前記磁気抵抗センサ膜に
信号検出電流を流すための電極と、前記磁気抵抗センサ
膜の電気抵抗変化を検知する手段を有する磁気抵抗セン
サであって、 前記第3の強磁性層が、酸化鉄FexO(但し、0.57
≦x≦0.70)からなる第1の反強磁性層(膜厚:0.
5〜10nm)の上に積層されており、 さらに、前記第1の反強磁性層が、酸化ニッケル(Ni
1-xCox)O(但し、0≦x≦0.5)からなる第2の反
強磁性層(膜厚:30nm以上)の上に積層されてお
り、 前記第3の強磁性層の飽和磁束密度と膜厚の積が、前記
第2の強磁性層の飽和磁束密度と膜厚との積よりも小さ
いことを特徴とする磁気抵抗センサ。1. A first ferromagnetic layer and a second ferromagnetic layer are stacked with a nonmagnetic conductive layer interposed therebetween, and the second and third ferromagnetic layers are stacked with a nonmagnetic spacer layer interposed therebetween. Are stacked, the second ferromagnetic layer and the third ferromagnetic layer are antiferromagnetically coupled via a nonmagnetic spacer layer, and the direction of magnetization of the first ferromagnetic layer is Makes an angle with the direction of magnetization of the second ferromagnetic layer when the external magnetic field is zero, and the relative angle between the direction of magnetization of the first ferromagnetic layer and the direction of magnetization of the second ferromagnetic layer. Magnetic film having a magnetoresistive sensor film whose electric resistance changes due to a change in the electrical angle, an electrode for flowing a signal detection current through the magnetoresistive sensor film, and means for detecting a change in electric resistance of the magnetoresistive sensor film met resistance sensor, the third ferromagnetic layer, iron oxide Fe x O (where, 0.57
≦ x ≦ 0.70) of the first antiferromagnetic layer (film thickness: 0.7) .
5-10 nm) , and the first antiferromagnetic layer is made of nickel oxide (Ni
1-x Co x ) O (where 0 ≦ x ≦ 0.5), which is laminated on a second antiferromagnetic layer (thickness: 30 nm or more) . magnetoresistive sensor product of saturation magnetic flux density and the film thickness may be smaller than the product of the saturation magnetic flux density and the film thickness Metropolitan of the second ferromagnetic layer.
およびそれらの合金である請求項1に記載の磁気抵抗セ
ンサ。2. The method according to claim 1, wherein the third ferromagnetic layer is made of Fe, Co, Ni.
2. The magnetoresistive sensor according to claim 1, wherein the magnetoresistive sensor is an alloy thereof.
し、0<x≦0.2)である請求項1に記載の磁気抵抗
センサ。3. The magnetoresistive sensor according to claim 1, wherein the third ferromagnetic layer is Co 1-x Fe x (where 0 <x ≦ 0.2).
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