Magnetoresistive element with conductive films and magnetic domain films overlapping a central active area

• US 6,040,962 A
• Filed: 05/14/1998
• Issued: 03/21/2000
• Est. Priority Date: 05/14/1997
• Status: Expired due to Term

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: Kanazawa, Kiyosumi, Nakagawa, Yoshiro
• Primary Examiner(s): EVANS, JEFFERSON A
• Application Number:
  US09/078,484
• Time in Patent Office: 677 Days
• Field of Search: 360/113, 360/126, 324/252, 338/32 R
• US Class Current: 360/322
• 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: G11B 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• CPC Class Codes: G11B 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 take precedence
• CPC Class Codes: G11B 5/3113 for improving the magnetic domain structure or avoiding the formation or displacement of undesirable magnetic domains
• CPC Class Codes: G11B 5/3116 Shaping of layers, poles or gaps for improving the form of the electrical signal transduced, e.g. for shielding, contour effect, equalizing, side flux fringing, cross talk reduction between heads or between heads and information tracks G11B5/3113, G11B5/245 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 5/3929 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: H10N 50/10 Magnetoresistive devices

Abstract

The present invention is directed to an MR element and a thin film magnetic head that do not cause an increase in the electrical resistance value due to the presence of dead zones. When forming passive areas that include magnetic domain control films and conductive films at the two sides of a central active area through a vacuum film formation method, the magnetic domain control films are formed under film forming conditions that are different from the film forming conditions under which the conductive films are formed to ensure that the degree to which the conductive films overlap the central active area is set larger than the degree to which the magnetic domain control films overlap the central active area.

Claims

1. A magnetoresistive element comprising:

a central active area; and

passive areas provided at two side ends of said central active area, each passive area including a magnetic domain control film and a conductive film;

wherein said magnetic domain control film of each passive area partially overlaps the surface of said central active area, each conductive film is laminated onto a surface of a respective magnetic domain control film and overlaps surfaces of said respective magnetic domain control film and said central active area, and the degree to which said conductive films overlap said surface of said central active area is set larger than the degree to which said magnetic domain control films overlap said surface of said central active area.

2. The magnetoresistive element of claim 1 wherein said degree to which said conductive films overlap the surface of said central active area is uniform at said two side ends of said central active area.

3. The magnetoresistive element of claim 1 wherein an overlapping area of said conductive films on said surface of said central active area extends beyond respective dead zones formed at said central active area.

4. The magnetoresistive element of claim 3 wherein said respective dead zones extend over approximately 0.3 to 1 μ

m.

5. The magnetoresistive element of claim 1 wherein said central active area includes a magnetic anisotropic magnetoresistive film.

6. The magnetoresistive element of claim 5 wherein said magnetic domain control film of said passive areas includes an anti-ferromagnetic film and applies a longitudinal bias to said magnetic anisotropic magnetoresistive film by utilizing anti-ferromagnetic/ferromagnetic exchange coupling occurring between said ferromagnetic film and said magnetic anisotropic magnetoresistive film.

7. The magnetoresistive element of claim 1 wherein said central active area is formed of a magnetoresistive film.

8. The magnetoresistive element of claim 7 wherein said magnetoresistive film includes a spin valve film.

9. The magnetoresistive element of claim 7 wherein said magnetoresistive film includes a ferromagnetic tunnel junction film.

10. The magnetoresistive element of claim 1 wherein said magnetic domain control film of said passive areas includes a hard magnetic film.

11. A thin film magnetic head including a magnetoresistive element comprising:

a central active area; and

passive areas provided at two side ends of said central active area, each passive area including a magnetic domain control film and a conductive film;

wherein said magnetic domain control film of each passive area partially overlaps the surface of said central active area, each conductive film is laminated onto a surface of a respective magnetic domain control film and overlaps surfaces of said respective magnetic domain control film and said central active area, and the degree to which said conductive films overlap said surface of said central active area is set larger than the degree to which said magnetic domain control films overlap said surface of said central active area.

12. The thin film magnetic head of claim 11 wherein said degree to which said conductive films overlap the surface of said central active area is uniforn at said two side ends of said central active area.

13. The thin film magnetic head of claim 11 wherein an overlapping area of said conductive films on said surface of said central active area extends beyond respective dead zones formed at said central active area.

14. The thin film magnetic head of claim 13 wherein said respective dead zones extend over approximately 0.15 to 0.5 μ

m.

15. The thin film magnetic head of claim 11 wherein said central active area includes a magnetic anisotropic magnetoresistive film.

16. The thin film magnetic head of claim 15 wherein said magnetic domain control film of said passive areas includes an anti-ferromagnetic film and applies a longitudinal bias to said magnetic anisotropic magnetoresistive film by utilizing anti-ferromagnetic/ferromagnetic exchange coupling occurring between said ferromagnetic film and said magnetic anisotropic magnetoresistive film.

17. The thin film magnetic head of claim 11 wherein said central active area is formed of a magnetoresistive film.

18. The thin film magnetic head of claim 17 wherein said magnetoresistive film includes a spin valve film.

19. The thin film magnetic head of claim 17 wherein said magnetoresistive film includes a ferromagnetic tunnel junction film.

20. The thin film magnetic head of claim 11 wherein said magnetic domain control film of said passive areas includes a hard magnetic film.

21. The thin film magnetic head of claim 11 wherein said magnetoresistive element is employed as a read element.

22. The thin film magnetic head of claim 21, further comprising:

a write element.