Magnetoresistive-effect element

• US 20010021089A1
• Filed: 02/28/2001
• Published: 09/13/2001
• Est. Priority Date: 03/02/2000
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Ikarashi, Minoru, Kano, Hiroshi, Mizuguchi, Tetsuya, Miyauchi, Teiichi
• Granted Patent: US 6,621,666 B2
• Time in Patent Office: Days
• 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 2005/3996 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: 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: Y10T 29/49048 Machining magnetic material [e.g., grinding, etching, polishing]

Abstract

The first ferromagnetic layer is made to show a single magnetic domain to prevent any magnetic wall from appearing. A pair of bias layers 4, 4 made of a hard magnetic material showing a high resistivity are arranged at opposite ends of a TMR thin film 3. As a result, the sense current flowing through the TMR thin film 3 is prevented from diverting to the bias layers 4, 4. Thus, a sufficiently strong bias magnetic field can be applied to the TMR thin film 3. As a result, the free layer 13 of the TMR thin film 3 is made to show a single magnetic domain to prevent any magnetic wall from appearing.

Claims

1. A magnetoresistive-effect element comprising:

a magnetoresistive-effect thin film operating as magnetism sensing section;

a pair of hard magnetic layers formed respectively at opposite ends of said magnetoresistive-effect thin film and adapted to apply a bias magnetic field to said magnetoresistive-effect thin film;

a pair of electrode layers formed oppositely on the main surfaces of the magnetoresistive-effect thin film and adapted to supply an electric current to said magnetoresistive-effect thin film; and

said hard magnetic layers having an electric resistivity not lower than 0.5 Ω

cm.

2. The magnetoresistive-effect element according to

claim 1

, wherein said magnetoresistive-effect thin film shows a tunnel junction type magnetoresistive-effect.

3. The magnetoresistive-effect element according to

claim 1

, wherein said magnetoresistive-effect thin film shows a giant magnetoresistive-effect.

4. The magnetoresistive-effect element according to

claim 1

, wherein said hard magnetic layers are made of a material containing an oxide as principal ingredient.

5. The magnetoresistive-effect element according to

claim 4

, wherein said hard magnetic layers are made of a material containing γ

Fe₂ O₃ as principal ingredient.

6. The magnetoresistive-effect element according to

claim 4

, wherein said hard magnetic layers are made of a material containing Co-γ

Fe₂O₃ as principal ingredient.

7. The magnetoresistive-effect element according to

claim 1

, wherein said hard magnetic layers are made of a material containing Co-Fe-MgF₂ as principal ingredient.