Magnetoresistive element, magnetic head, magnetic memory and magnetic recording apparatus using the same

• US 6,842,317 B2
• Filed: 10/22/2003
• Issued: 01/11/2005
• Est. Priority Date: 04/22/2002
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Sugita, Yasunari, Odagawa, Akihiro, Matsukawa, Nozomu
• Primary Examiner(s): KLIMOWICZ, WILLIAM JOSEPH
• Application Number:
  US10/692,362
• Publication Number:
  US 20040080876A1
• Time in Patent Office: 447 Days
• Field of Search: 360/324.2, 360/324.1, 360/324.11, 360/324.12, 365/158, 365/171, 365/173
• 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 5/00 Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor G11B11/00 and G11B13/00 take precedence
• 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 5/3916 Arrangements in which the active read-out elements are coupled to the magnetic flux of the track by at least one magnetic thin film flux guide
• 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: H01F 10/3254 the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: H10N 50/85 Magnetic active materials

Abstract

A magnetoresistive element includes a multilayer film configuration including: a tunnel insulation layer; and a pair of magnetic layers that are laminated with the tunnel insulation layer interposed therebetween. A resistance value of the magnetoresistive element varies with a relative angle between magnetic orientations of both of the magnetic layers, and at least one of the magnetic layers includes a magnetic film having a thermal expansion coefficient not greater than a value obtained by adding 2×10⁻⁶/K to a thermal expansion coefficient of the tunnel insulation layer. The thus configured magnetoresistive element can exert excellent thermal stability. The use of such a magnetoresistive element can realize a magnetic head, a magnetic memory element and a magnetic recording apparatus with excellent thermal stability.

Claims

1. A magnetoresistive element comprising a multilayer film configuration comprising:

a tunnel insulation layer; and

a pair of magnetic layers that are laminated with the tunnel insulation layer interposed therebetween,

wherein a resistance value of the magnetoresistive element varies with a relative angle between magnetic orientations of both of the magnetic layers, and

at least one of the magnetic layers comprises a magnetic film having a thermal expansion coefficient not greater than a value obtained by adding 2×

10<sup>−

6</sup>/K to a thermal expansion coefficient of the tunnel insulation layer.

2. The magnetoresistive element according to claim 1, wherein the thermal expansion coefficient of the magnetic film is not greater than the thermal expansion coefficient of the tunnel insulation layer.

3. The magnetoresistive element according to claim 1, wherein the magnetic film is in contact with the tunnel insulation layer.

4. The magnetoresistive element according to claim 1, wherein the tunnel insulation layer comprises at least one compound selected from the group consisting of an oxide, a nitride and an oxynitride of Al.

5. The magnetoresistive element according to claim 1, wherein the magnetic film comprises an invar alloy.

6. The magnetoresistive element according to claim 5, wherein the invar alloy has a composition represented by the formula Fe_x—

Ni_y—

Co_z,

where, in the formula Fe_x—

Ni_y—

Co_z, x, y and z are numbers satisfying the following relationships;

x+y+z=1,

0.5≦

x≦

0.7,

 

0.3≦

y≦

0.45, and

0≦

z≦

0.2.

7. The magnetoresistive element according to claim 5, wherein the invar alloy has a composition represented by the formula Fe_1-a—

Pt_a,

where, in the formula Fe_1-a—

Pt_a a is a number satisfying the following relationship;

0.15≦

a≦

0.45.

8. The magnetoresistive element according to claim 5, wherein the invar alloy has a composition represented by the formula Fe_1-b—

Pd_b,

where, in the formula Fe_1-b—

Pd_b, b is a number satisfying the following relationship;

0.2≦

b≦

0.45.

9. The magnetoresistive element according to claim 1, wherein the magnetic film comprises an amorphous alloy containing Fe as a main component.

10. The magnetoresistive element according to claim 6, wherein the amorphous alloy has a composition represented by the formula Fe_1-c—

M_c,

where, in the formula Fe_1-c—

M_c, M denotes at least one element selected from the group consisting of B, P, Si, Zr and Hf, and

c is a number satisfying the following relationship;

0.05≦

c≦

0.3.

11. The magnetoresistive element according to claim 1, further comprising an antiferromagnetic layer.

12. The magnetoresistive element according to claim 11, wherein the antiferromagnetic layer comprises Mn.

13. A magnetic head, comprising:

the magnetoresistive element according to claim 1; and

a shield for restricting introduction of a magnetic field other than a magnetic field to be detected by the magnetoresistive element into the magnetoresistive element.

14. A magnetic recording apparatus, comprising:

the magnetic head according to claim 13; and

a magnetic recording medium from which magnetic information can be read out by the magnetic head.

15. A magnetic head, comprising:

the magnetoresistive element according to claim 1; and

a yoke for introducing a magnetic field to be detected by the magnetoresistive element to the magnetoresistive element.

16. A magnetic recording apparatus, comprising:

the magnetic head according to claim 14; and

a magnetic recording medium from which magnetic information can be read out by the magnetic head.

17. A magnetic memory, comprising:

the magnetoresistive element according to claim 1;

conductive lines for recording information on the magnetoresistive element; and

conductive lines for reading out the information.