Magnetoresistance effect multilayer film with ferromagnetic film sublayers of different ferromagnetic material compositions

• US 6,011,674 A
• Filed: 04/02/1996
• Issued: 01/04/2000
• Est. Priority Date: 06/08/1990
• Status: Expired due to Fees

• Current Assignee: Hitachi Global Storage Technologies Japan Limited (Western Digital Corporation)
• Original Assignee: Hitachi, Ltd.
• Inventors: Shiiki, Kazuo, Kobayashi, Toshio, Takano, Hisashi, Koyama, Naoki, Nakao, Takeshi, Akagi, Kyo, Tanabe, Hideo, Shimizu, Noboru, Suzuki, Mikio, Yuito, Isamu, Moriwaki, Eijin, Futamoto, Masaaki, Matsuda, Yoshibumi, Kitada, Masahiro, Takagaki, Tokuho, Nakatani, Ryoichi, Fukuoka, Hirotsugu, Munemoto, Takayuki, Kugiya, Fumio, Miyamura, Yoshinori
• Primary Examiner(s): Renner, Craig A.
• Application Number:
  US08/626,333
• Time in Patent Office: 1,372 Days
• Field of Search: 360/113
• US Class Current: 360/324.2
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G11B 2005/0002 Special dispositions or recording techniques
• CPC Class Codes: G11B 2005/0016 of magnetoresistive transducers
• CPC Class Codes: G11B 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• CPC Class Codes: G11B 5/3903 using magnetic thin film layers or their effects, the films being part of integrated structures
• CPC Class Codes: G11B 5/3909 Arrangements using a magnetic tunnel junction
• CPC Class Codes: G11B 5/3929 Disposition of magnetic thin films not used for directly coupling magnetic flux from the track to the MR film or for shielding
• CPC Class Codes: G11B 5/3967 Composite structural arrangements of transducers, e.g. inductive write and magnetoresistive read G11B5/3906 takes precedence
• CPC Class Codes: G11B 5/398 Specially shaped layers
• CPC Class Codes: H01F 10/324 Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer
• CPC Class Codes: H01F 10/3254 the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
• CPC Class Codes: H01F 10/3268 the exchange coupling being asymmetric, e.g. by use of additional pinning, by using antiferromagnetic or ferromagnetic coupling interface, i.e. so-called spin-valve [SV] structure, e.g. NiFe/Cu/NiFe/FeMn
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: Y10T 29/49032 Fabricating head structure or component thereof
• CPC Class Codes: Y10T 29/49043 Depositing magnetic layer or coating
• CPC Class Codes: Y10T 29/49044 Plural magnetic deposition layers
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magnetoresistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-denisity recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.

Claims

1. A multilayer film, comprising:

plural magnetic layers;

a nonmagnetic layer in contact with and magnetically separating each adjacent pair of said plural magnetic layers; and

an antiferromagnetic layer contacting one of the plural magnetic layers so that an exchange bias magnetic field is applied from the antiferromagnetic layer to the magnetic layer contacting the antiferromagnetic layer, an angle with respect to a magnetization direction of each of the plural magnetic layers being varied by a magnetic field applied from outside, and an electrical resistivity being varied due to the angles of the respective magnetization directions, wherein the electrical resistivity is lowest when the magnetization directions are parallel to each other, and wherein the electrical resistivity is highest when the magnetization directions are antiparallel to each other;

wherein the magnetic layer contacting the antiferromagnetic layer includes at least two sublayers which consist of different respective ferromagnetic compositions; and

wherein one of the sublayers has a face-centered cubic structure and directly contacts the antiferromagnetic layer, whereby a γ

-phase structure in the antiferromagnetic layer is more easily attained.

2. A multilayer film according to claim 1, wherein one of the sublayers consists mainly of Ni and Fe, and contacts the antiferromagnetic layer.

3. A multilayer film according to claim 1, wherein one of the sublayers has a substantially similar crystal structure to that of the antiferromagnetic layer, and contacts the antiferromagnetic layer.

4. A multilayer film according to claim 3, wherein the antiferromagnetic layer includes an alloy having Mn.

5. A multilayer structure, comprising:

a multilayer film including plural magnetic layers;

a nonmagnetic layer for magnetically separating each adjacent pair of said plural magnetic layers; and

an antiterroiagnetic layer contacting one or the plural magnetic layers so that an exchange bias magnetic field is applied from the antiferromagnetic layer to the magnetic layer contacting the antiferrormagnetic layer, an angle with respect to a magnetization direction of each of the plural magnetic layers being varied by a magnetic field applied from outside, and an electrical resistivity being varied due to the angles of the respective magnetization directions, wherein the electrical resistivity is lowest when the magnetization directions are parallel to each other, and wherein the electrical resistivity is highest when the magnetization directions are antiparallel to each other; and

a nonmagnetic metal layer on which the multilayer film is provided;

wherein the magnetic layer contacting the antiferromagnetic layer includes at least two sublayers which consist of different respective ferromagnetic compositions; and

wherein one of the sublayers has a face-centered cubic structure and directly contacts the antiferromagnetic layer, whereby a γ

-phase structure in the antiferromagnetic layer is more easily attained.

6. A magnetoresistance effect element, comprising:

a multilayer film including plural magnetic layers;

a nonmagnetic layer for magnetically separating each adjacent pair of said plural magnetic layers; and

an antiferromagnetic layer contacting one of the plural magnetic layers so that an exchange bias magnetic field is applied from the antiferromagnetic layer to the magnetic layer contacting the antiferromagnetic layer, an angle with respect to a magnetization direction of each of the plural magnetic layers being varied by an external magnetic field applied from outside, and an electrical resistivity being varied due to the angles of the respective magnetization directions, wherein the electrical resistivity is lowest when the magnetization directions are parallel to each other, and wherein the electrical resistivity is highest when the magnetization directions are antiparallel to each other; and

a pair of electrodes connected at opposed ends of the multilayer film, such that a voltage applied to the pair of electrodes varies in accordance with a variation of the electrical resistivity between the pair of electrodes, for detecting the external magnetic field;

wherein the magnetic layer contacting the antiferromagnetic layer includes at least two sublayers which consist of different respective ferromagnetic compositions; and

wherein one of the sublayers has a face-centered cubic structure and directly contacts the antiferromagnetic layer, whereby a γ

-phase structure in the antiferromagnetic layer is more easily attained.