Magnetoresistive effect element

• US 5,880,911 A
• Filed: 06/25/1997
• Issued: 03/09/1999
• Est. Priority Date: 03/24/1994
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Yamamoto, Hidefumi, Hayashi, Kazuhiko, Fujikata, Jun-Ichi, Ishihara, Kunihiko
• Primary Examiner(s): OMETZ, DAVID LOUIS
• Application Number:
  US08/882,229
• Time in Patent Office: 622 Days
• Field of Search: 360/113, 360/125, 360/126, 338/32 R, 324/252
• US Class Current: 360/324
• 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 2005/0016 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 5/3925 the two parts being thin films
• CPC Class Codes: G11B 5/3932 Magnetic biasing films
• CPC Class Codes: G11B 5/399 with intrinsic biasing, e.g. provided by equipotential strips
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

The magnetoresistive effect element in accordance with the invention has several aspects. For instance, the magnetoresistive effect element includes an artificial lattice multilayered structure composed of a thin magnetic layer and a non-magnetic layer at least once successively deposited, and a bias field applying device for applying a bias magnetic field to the artificial lattice multilayered structure so that an orientation of residual magnetization of one of the thin magnetic layers having a greater coercive force than that of an adjacent thin magnetic layer, is the same as an orientation of a bias magnetic field to be applied to the artificial lattice multilayered structure. The magnetoresistive effect element provides enhanced regenerated outputs and also improves the symmetry of regenerated waveforms.

Claims

1. A magnetoresistive effect element comprising:

an artificial lattice multilayered structure comprising a thin magnetic layer and a non-magnetic layer at least once successively deposited, one of said the magnetic layers having a coercive force HC₂, and another thin magnetic layer deposited adjacent to said one of said thin magnetic layer through said non-magnetic layer, having a coercive force H_C3 which is greater than said coercive force H_C2 (0<

H_C2 <

H_C3) ; and

bias field applying means for applying a bias magnetic field to said artificial lattice multilayered structure in a same orientation and polarity as a residual magnetization of said another thin magnetic layer having coercive force H_C3, to thereby suppress the influence of magnetostatic coupling in said one of said thin magnetic layer having coercive force H_C2.

2. The magnetoresistive effect element as recited in claim 1, wherein said bias field applying means includes a shunt layer comprising a non-magnetic layer having a thickness ranging from 2 nm to 20 nm both inclusive.

3. The magnetoresistive effect element as recited in claim 1, wherein said bias field applying means includes a permanent magnet for producing a magnetic field, said permanent magnet having a residual magnetic flux density ranging from 1000 G to 5000 G both inclusive.

4. The magnetoresistive effect element as recited in claim 1, wherein said bias field applying means includes means for generating an induction field by means of an electrical current.

5. The magnetoresistive effect element as recited in claim 1, wherein said bias field applying means includes a soft magnetic film which generates a leakage magnetic field.

6. The magnetoresistive effect element as recited in claim 1, wherein said bias field applying means includes means for running a sense current through two of said artificial lattice multilayered structures to thereby generate the bias magnetic field.

7. A magnetoresistive effect element as recited in claim 1, further comprising:

yokes being overlapped with said artificial lattice multilayered structure at opposite ends of said multilayered structure, an overlapping portion of said yokes with said artificial lattice multilayered structure having a length up to 2.0 μ

m inclusive.

8. The magnetoresistive effect element as recited in claim 7, wherein said artificial lattice multilayered structure further comprises a thin antiferromagnetic layer so that said artificial lattice multilayered structure is composed of said one said thin magnetic layers, said thin non-magnetic layer, said another thin magnetic layer and said thin antiferromagnetic layer at least once successively deposited in this order.

9. The magnetoresistive effect element as recited in claim 8, wherein said artical lattice multilayered structure further comprises a metallic thin layer so that said artical lattice multilayered structure is composed of said metallic thin layer, said one said thin magnetic layers, said thin non-magnetic layer, said another thin magnetic layer and said thin antiferromagnetic layer at least once successively deposited in this order.

10. A magnetoresistive effect element as recited in claim 1, further comprising:

yokes positioned relative to said artificial lattice multilayered structure, said artificial lattice multilayered structure having a magnetoresistive height up to 10 μ

m inclusive.

11. The magnetoresistive effect element as recited in claim 10, wherein said artificial lattice multilayered structure further comprises a thin antiferromagnetic layer so that said artificial lattice multilayered structure is composed of said one of said thin magnetic layers, said thin non-magnetic layer, said another thin magnetic layer and said thin antiferromagnetic layer at least once successively deposited in this order.

12. The magnetoresistive effect element as recited in claim 11, wherein said artificial lattice multilayered structure further comprises a metallic thin layer so that said artificial lattice multilayered structure is composed of said metallic thin layers, said thin magnetic layers, said thin non-magnetic layer, said another thin magnetic layer and said thin antiferromagnetic layer successively at least once deposited in this order.

13. A magnetoresistive effect element as recited in claim 1, further comprising:

a ring-shaped yoke positioned relative to said artificial lattice multilayered structure, a distance between a surface from which a magnetic field is to be detected and said artificial lattice multilayered structure being greater than a gap depth of said ring-shaped yoke, and said gap depth being up to 5 μ

m inclusive.

14. The magnetoresistive effect element as recited in claim 13, wherein said artical lattice multilayered structure further comprises a thin antiferromagnetic layer so that said artificial lattice multilayered structure is composed of said one of said another thin magnetic layers, said thin non-magnetic layer, said another thin magnetic layer and said thin antiferromagnetic layer at least once successively deposited in this order.

15. The magnetoresistive effect element as recited in claim 14, wherein said artificial lattice multilayered structure further comprises a metallic thin layer so that said artificial lattice multilayered structure is composed of said metallic thin layer, said thin magnetic layer, said thin non-magnetic layer, said another one of said thin magnetic layers and said thin antiferromagnetic layer at least once successively deposited in this order.

16. A magnetoresistive effect element comprising:

an artificial lattice multilayered structure comprising a thin magnetic layer and a non-magnetic layer at least once successively deposited, one of said thin magnetic layers having a coercive force H_C2, and another thin magnetic layer deposited adjacent to said one of said thin magnetic layers through said non-magnetic layer, having a coercive force H_C3 which is greater than said coercive force H_C2 (0<

H_C2 <

H_C3);

yokes positioned relative to said artificial lattice multilayered structure with a non-magnetic insulating layer disposed between said yokes and said artificial lattice multilayered structure; and

means for applying an electrical current to said artificial lattice multilayered structure to run said electrical current in a negative direction of an X axis,

wherein a Y axis is defined to be a magnetization orientation when a magnetic field is equal to zero after a magnetization of said another thin magnetic layer has been saturated, and a Z axis is defined to be a direction from said artificial lattice multilayered structure towards said yokes perpendicularly to said artificial lattice multilayered structure.

17. The magnetoresistive effect element as recited in claim 16, wherein said yokes are disposed so that said yokes are overlapped with said artificial lattice multilayered structure at opposite ends of said multilayered artificial lattice structure.

18. The magnetoresistive effect element as recited in claim 17, wherein an overlapping portion of said yokes with said artificial lattice multilayered structure has a length up to 2.0 μ

m inclusive.

19. The magnetoresistive effect element as recited in claim 16, wherein said artificial lattice multilayered structure has a magnetoresistive height up to 10 μ

m inclusive.

20. The magnetoresistive effect element as recited in claim 16, wherein said artificial lattice multilayered structure further comprises a thin antiferromagnetic layer so that said artificial lattice multilayered structure is composed of said one of said thin magnetic layers, said thin non-magnetic layer, said another thin magnetic layer and said thin antiferromagnetic layer at least once successively deposited in this order.

21. The magnetoresistive effect element as recited in claim 20, wherein said artificial layer multilayered structure further comprises a metallic layer so that said artificial layer multilayered structure is composed of said metallic layers, said thin one of said magnetic layer, said thin non-magnetic layer, said another thin magnetic layer and said thin antiferromagnetic layer at least once successively deposited in this order.