Magnetoresistive effect transducer having longitudinal bias layer directly connected to free layer

• US 20030035256A1
• Filed: 09/12/2002
• Published: 02/20/2003
• Est. Priority Date: 11/30/1998
• Status: Active Grant

• Current Assignee: Detroit Diesel Corporation (Mercedes-Benz Group AG)
• Original Assignee: NEC Corporation
• Inventors: Ishi, Tsutomu, Ishiwata, Nobuyuki, Nakada, Masafumi, Hayashi, Kazuhiko, Ohashi, Keishi, Kamijo, Atsushi, Honjou, Hiroaki, Matsutera, Hisao, Tsuge, Hisanao, Fujikata, Jun-Ichi, Ishihara, Kunihiko
• Granted Patent: US 6,950,290 B2
• Time in Patent Office: Days
• US Class Current: 360/324.12
• 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 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 5/3932 Magnetic biasing films
• CPC Class Codes: G11B 5/3967 Composite structural arrangements of transducers, e.g. inductive write and magnetoresistive read G11B5/3906 takes precedence

Abstract

In a magnetoresistive effect transducer including a pinning layer, a pinned layer, a free layer and a non-magnetic layer inserted between the pinned layer and the free layer, a longitudinal bias layer is connected directly to a part of the free layer to apply a bias magnetic field to the free layer, thus biasing a magnetization direction of the free layer so that the magnetization direction of the free layer coincides with that of the longitudinal bias layer.

Claims

1. A magnetoresistive effect transducer comprising:

a pinning layer;

a pinned layer;

a free layer;

a non-magnetic layer inserted between said pinned layer and said free layer; and

a longitudinal bias layer, connected directly to a part of said free layer, for applying a bias magnetic field to said free layer to bias a magnetization direction of said free layer so that the magnetization direction of said free layer coincides with that of said longitudinal bias layer,

a sense current flowing between said pinned layer and said free layer through said non-magnetic layer.

2. The transducer as set forth in claim 1, wherein said non-magnetic layer is made of insulating material, so that said free layer, said pinned layer and said non-magnetic layer form a ferromagnetic tunneling junction (MTJ) structure.

3. The transducer as set forth in claim 1, wherein said non-magnetic layer is made of conductive material, so that said free layer, said pinned layer and said non-magnetic layer form a spin valve structure.

4. The transducer as set forth in claim 1, further comprising an interface control layer, inserted between said free layer and said longitudinal bias layer, for controlling said bias magnetic field.

5. The transducer as set forth in claim 1, wherein said free layer is formed on said non-magnetic layer and said non-magnetic layer is formed on said pinned layer,

said free layer having a smaller pattern than said pinning layer.

6. The transducer as set forth in claim 1, wherein said pinning layer is formed on said pinned layer, said pinned layer is formed on said non-magnetic layer, and said non-magnetic layer is formed on said free layer,

said pinning layer having a smaller pattern than said free layer.

7. The transducer as set forth in claim 1, further comprising a pinning layer, formed on an outer surface of said pinned layer, for providing an anisotropic exchange coupling with said pinned layer.

8. A magnetoresistive effect transducer comprising:

a pinning layer;

a pinned layer formed on said pinning layer;

a non-magnetic layer formed on said pinned layer;

a free layer formed on said non-magnetic layer,

said free layer having a smaller pattern than said pinning layer,

a sense current flowing between said pinned layer and said free layer through said non-magnetic layer.

9. The transducer as set forth in claim 8, wherein said non-magnetic layer is made of insulating material, so that said pinned layer, said non-magnetic layer and said free layer form a ferromagnetic tunneling junction (MTJ) structure.

10. The transducer as set forth in claim 8, wherein said non-magnetic layer is made of conductive material, so that said pinned layer, said non-magnetic layer and said free layer form a spin valve structure.

11. A magnetoresistive effect transducer comprising:

a free layer;

a non-magnetic layer formed on said free layer;

a pinned layer formed on said non-magnetic layer; and

a pinning layer formed on said pinned layer,

said pinning layer having a smaller pattern than said free layer,

a sense current flowing between said free layer and said pinned layer through said non-magnetic layer.

12. The transducer as set forth in claim 11, wherein said non-magnetic layer is made of insulating material, so that said free layer, said non-magnetic layer and said pinned layer form a ferromagnetic tunneling junction (MTJ) structure.

13. The transducer as set forth in claim 11, wherein said non-magnetic layer is made of conductive material, so that said free layer, said non-magnetic layer and said pinned layer form a spin valve structure.

14. A magnetoresistive effect transducer comprising:

a substrate;

a lower magnetic shield layer formed on said substrate;

a pinning layer formed on said lower magnetic shield layer;

a pinned layer formed on said pinning layer, said pinning layer providing an exchange coupling with said pinned layer;

a non-magnetic layer formed on said pinned layer, said non-magnetic layer being made of one of insulating material and conductive material;

a free layer formed on said non-magnetic layer;

a pair of longitudinal bias layers formed on said free layer;

a pair of insulating layers each formed on one of said longitudinal bias layers; and

an upper magnetic shield layer formed on said free layer and said insulating layers,

a sense current flowing between said pinned layer and said free layer through said non-magnetic layer.

15. The transducer as set forth in claim 14, further comprising at least one of a lower electrode layer and an upper electrode layer,

said lower electrode layer being inserted between said lower magnetic shield layer and said pinning layer,

said upper electrode layer being inserted between said free layer and said upper magnetic shield layer.

16. A magnetoresistive effect transducer comprising:

a substrate;

a lower magnetic shield layer formed on said substrate;

a pinning layer formed on said lower magnetic shield layer;

a pinned layer formed on said pinning layer, said pinning layer providing an anisotropic exchange coupling with said pinned layer;

a non-magnetic layer formed on said pinned layer, said non-magnetic layer being made of one of insulating material and conductive material;

a free layer formed on said non-magnetic layer;

a longitudinal bias layer formed on said free layer; and

an upper magnetic shield layer formed on said longitudinal bias layer,

a sense current flowing between said pinned layer and said free layer through said non-magnetic layer.

17. The transducer as set forth in claim 16, further comprising at least one of a lower electrode layer and an upper electrode layer,

said lower electrode layer being inserted between said lower magnetic shield layer and said pinning layer,

said upper electrode layer being inserted between said free layer and said upper electrode layer.

18. A magnetoresistive effect transducer comprising:

a substrate;

a lower magnetic shield layer formed on said substrate;

a pinning layer formed on said lower magnetic shield layer;

a pinned layer formed on said pinning layer, said pinning layer providing an exchange coupling with said pinned layer;

a non-magnetic layer formed on said pinned layer, said non-magnetic layer being made of one of insulating material and conductive material;

a patterned free layer formed on said non-magnetic layer;

a pair of longitudinal bias layers formed on sides of said free layer; and

an upper magnetic shield layer formed on said free layer and said longitudinal bias layers,

a sense current flowing between said pinned layer and said free layer through said non-magnetic layer.

19. The transducer as set forth in claim 18, further comprising a insulating layer inserted between said non-magnetic layer and one of said longitudinal bias layers.

20. The transducer as set forth in claim 18, further comprising at least one of a lower electrode layer and an upper electrode layer,

said lower electrode layer being inserted between said lower magnetic shield layer and said pinning layer,

said upper electrode layer being inserted between said free layer and said upper magnetic shield layer.

21. A magnetoresistive effect transducer comprising:

a substrate;

a lower magnetic shield layer formed on said substrate;

a pinning layer formed on said lower magnetic shield layer;

a pinned layer formed on said pinning layer, said pinning layer providing an exchange coupling with said pinned layer;

a non-magnetic layer formed on said pinned ferromagnetic layer, said non-magnetic layer being made of one of insulating material and conductive material;

a patterned free layer formed on said non-magnetic layer;

a patterned interface control layer formed on said patterned free layer;

a longitudinal bias layer formed on said patterned interface control layer, said patterned interface control layer controlling a bias magnetic field applied by said longitudinal bias layer to said free layer;

a insulating layer formed on sides of said longitudinal bias layer, said interface control layer and said free layer; and

an upper magnetic shield layer formed on said patterned longitudinal bias layer and said non-magnetic layer,

a sense current flowing between said pinned layer and said free layer through said non-magnetic layer.

22. The transducer as set forth in claim 21, wherein said patterned free layer, said patterned interface control layer and said patterned longitudinal bias layer form a mesa structure.

23. The transducer as set forth in claim 21, further comprising at least one of a lower electrode layer and an upper electrode layer,

said lower electrode layer being inserted between said lower magnetic shield layer and said pinning layer,

said upper electrode layer inserted between said longitudinal bias layer and said upper magnetic shield layer.

24. A magnetoresistive effect transducer comprising:

a substrate;

a lower magnetic shield layer formed on said substrate;

a free layer formed on said lower magnetic shield layer;

a pair of longitudinal bias layers formed on said free layer;

a patterned non-magnetic layer formed on said free layer between said longitudinal bias layers, said patterned non-magnetic layer being made of one of insulating material and conductive material;

a patterned pinned layer formed on said non-magnetic layer;

a patterned pinning layer, formed on said patterned pinned layer, for providing an exchange coupling with said patterned pinned layer;

a pair of insulating layers formed on said free layer, said longitudinal bias layer on sides of said patterned barrier layer, said patterned pinned layer and said patterned pinning layer; and

an upper magnetic shield layer formed on said patterned pinning layer and said insulating layers,

a sense current flowing between said free layer and said patterned pinned layer through said non-magnetic layer.

25. The transducer as set forth in claim 24, further comprising at least one of a lower electrode layer and an upper electrode layer,

said lower electrode layer inserted between said lower magnetic shield layer and said free layer,

said upper electrode layer being inserted between said patterned pinning layer and said upper magnetic shield layer.

26. A magnetoresistive effect transducer comprising:

a substrate;

a lower magnetic shield layer formed on said substrate;

a pair of longitudinal bias layers formed on said lower magnetic layer;

a free layer formed on said lower magnetic shield layer and said longitudinal bias layers;

a non-magnetic layer formed on said free layer between said longitudinal layers, said non-magnetic layer being made of one of insulating material and conductive material;

a patterned pinned layer formed on said non-magnetic layer;

a patterned pinning layer, formed on said patterned pinned layer, for providing an antisotropic exchange coupling with said patterned pinned layer;

an insulating layer formed on said patterned non-magnetic layer on sides of said patterned pinned layer and said patterned pinning layer; and

an upper magnetic shield layer formed on said patterned pinning layer and said insulating layer,

a sense current flowing between said free layer and said patterned pinned layer through said non-magnetic layer.

27. The transducer as set forth in claim 26, wherein said non-magnetic layer and said free layer are patterned so that said non-magnetic layer and said free layer have larger patterns than said pinning layer.

28. The transducer as set forth in claim 26, wherein said non-magnetic layer and said free layer are patterned so that said non-magnetic layer and said free layer have substantially the same patterns as said patterned pinned layer and said pinning layer.

29. The transducer as set forth in claim 26, further comprising at least one of a lower electrode layer and an upper electrode layer,

said lower electrode layer being inserted between said lower magnetic shield layer and said free shield layer,

said upper electrode layer being inserted between said pinning and said upper magnetic shield.

30. A method for manufacturing a magnetoresistive effect transducer, comprising the steps of:

forming a magnetoresistive structure including at least a free layer, a non-magnetic layer made of one of insulating material and conductive material and a pinned layer;

patterning an uppermost layer of said free layer, said barrier layer, said pinned layer and said pinning layer, so that said uppermost layer has a smaller pattern than other layers.

31. A magnetic write/read apparatus including a head slider, a write head and a read head formed on said head slider, wherein said read head comprises:

a pinned layer;

a free layer;

a non-magnetic layer inserted between said pinned layer and said free layer said non-magnetic layer being made of one of insulating material and conductive material; and

a longitudinal bias layer, connected directly to a part of said free layer, for applying a bias magnetic field to said free layer to bias a magnetization direction of said free layer so that the magnetization direction of said free layer coincides with that of said longitudinal bias layer.

32. A magnetic write/read apparatus including a head slider, a write head and a read head formed on said head slider, wherein said read head comprises:

a pinned layer;

a non-magnetic layer formed on said pinned layer, said non-magnetic layer being made of one of insulating material and conductive material;

a free layer formed on said non-magnetic layer,

said free layer having a smaller pattern than said pinning layer.

33. A magnetic write/read apparatus including a head slider, a write head and a read head formed on said head slider, wherein said read head comprises:

a free layer;

a non-magnetic layer formed on said free ferromagnetic layer, said non-magnetic layer being made of one of insulating material and conductive material;

a pinned layer formed on said non-magnetic layer,

said pinning layer having a smaller pattern than said free layer.