Magnetic sensing element comprising antiferromagnetic layer laminated on free magnetic layer

• US 6,995,961 B2
• Filed: 03/27/2003
• Issued: 02/07/2006
• Est. Priority Date: 03/29/2002
• Status: Expired due to Fees

• Current Assignee: TDK Corporation
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Ishizone, Masahiko, Hasegawa, Naoya, Umetsu, Eiji, Koike, Fumihito
• Primary Examiner(s): EVANS, JEFFERSON A
• Application Number:
  US10/400,946
• Publication Number:
  US 20030184925A1
• Time in Patent Office: 1,048 Days
• Field of Search: 360/324.1, 360/324.11, 360/324.12, 360/324.2
• 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 5/3903 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

Abstract

Changes of the direction of magnetization at the central region of the free magnetic layer are facilitated by using a layer of a magnetic material having a small exchange stiffness constant such as a Ni_aFe_b layer (a and b are represented in at %, and satisfy the relation of a>80 and a+b=100) and NiFeX layer (X is at least one element selected from Mn, Cu, Zn, Ti, Al, Ge, Si, Cr, V, Sn, Ir, Ru, Nb, Sb, W, Mo, Os and Ta) for the magnetic material layer of the free magnetic layer.

Claims

1. A magnetic sensing element having a multilayer comprising a first antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic material layer and a free magnetic layer laminated in this order,

a pair of second antiferromagnetic layers formed with a distance therebetween in a track width direction so as to be stacked at least on both side regions of the free magnetic layer in the track width direction,

said free magnetic layer including at least one of a Ni_aFe_b layer, a NiFeX layer, an amorphous Co alloy layer containing an amorphous Co based magnetic material, and a CoFeX layer,

wherein a and b in Ni_aFe_b represented by at % satisfy the relation of a>

80 with a+b=100,

wherein X in the NiFeX layer represents at least one element selected from Mn, Cu, Zn, Ti, Al, Ge, Si, Cr, V, Sn, Ir, Ru, Nb, Sb, W, Mo, Os and Ta,

wherein X in the CoFeX layer represents at least one element selected from Ti, Al, Mn, Si, V, Cr, Ta, Zn, Sb, Ge, Mo and W,

wherein the free magnetic layer comprises a (Co_xFe_y)_eCr_f layer as one of an uppermost layer and lowermost layer closest to the second antiferromagnetic layer, x and y are represented by an at % ratio of Co to Fe satisfying the relation of x+y=1, and e and f are represented by at % satisfying the relations of 0<

f<

20 and e+f=100.

2. The magnetic sensing element according to claim 1, wherein an optical track width O-Tw defined by the distance between the second antiferromagnetic layers in the track width direction is at most 0.15 μ

m.

3. The magnetic sensing element according to claim 2, wherein the optical track width is at most 0.12 μ

m.

4. The magnetic sensing element according to claim 3, wherein the optical track width is at most 0.10 μ

m.

5. The magnetic sensing element according to claim 1, wherein the free magnetic layer has a structure in which a magnetic layer containing Co is laminated on at least one of the Ni_aFe_b layer and NiFeX layer.

6. The magnetic sensing element according to claim 1, wherein the free magnetic layer has at least a structure comprising at least one of the amorphous Co alloy layer comprising the amorphous Co based magnetic material and the CoFeX layer, and a laminated structure of both layers.

7. The magnetic sensing element according to claim 6, wherein one of a magnetic layer having a smaller resistivity than a resistivity of the amorphous Co alloy layer is laminated under the amorphous Co alloy layer and a magnetic layer having a smaller resistivity than a resistivity of the CoFeX layer is laminated under the CoFeX layer.

8. The magnetic sensing element according to claim 7, wherein the magnetic layer having the small resistivity comprises at least one of the NiFe layer and NiFeX layer.

9. The magnetic sensing element according to claim 1, wherein e and f are represented by at % satisfying the relation of 5<

f<

15.

10. The magnetic sensing element according to claim 9, wherein the (Co_xFe_y)_eCr_f layer has a thickness of at least 2 Å

and at most 10 Å

.

11. The magnetic sensing element according to claim 10, wherein the (Co_xFe_y)_eCr_f layer has a thickness of at least 3 Å

and at most 6 Å

.

12. The magnetic sensing element according to claim 1, wherein the (Co_xFe_y)_eCr_f layer has a thickness of at least 2 Å

and at most 10 Å

.

13. The magnetic sensing element according to claim 12, wherein the (Co_xFe_y)_eCr_f layer has a thickness of at least 3 Å

and at most 6 Å

.

14. The magnetic sensing element according to claim 1, wherein exchange stiffness constants of the magnetic materials constituting the Ni_aFe_b layer, NiFeX layer, amorphous Co alloy layer, and CoFeX layer are smaller than an exchange stiffness constant of a magnetic material represented by a composition formula of Ni₈₀Fe₂₀.

15. The magnetic sensing element according to claim 1, wherein a second nonmagnetic layer comprising one of Cr and Cu is formed between the second antiferromagnetic layer and free magnetic layer.

16. The magnetic sensing element according to claim 1, wherein a ferromagnetic layer is formed one of between the second antiferromagnetic layer and free magnetic layer and between the second antiferromagnetic layer and nonmagnetic layer.

17. The magnetic sensing element according to claim 1, wherein a surface of the second antiferromagnetic layer comprises an opening, and a groove having a prescribed width is formed in the track width direction.

18. The magnetic sensing element according to claim 17, wherein a side face of the groove is perpendicular to the surface of the second antiferromagnetic layer.

19. The magnetic sensing element according to claim 18, wherein a bottom face of the groove is provided within the second antiferromagnetic layer.

20. The magnetic sensing element according to claim 19, wherein a thickness of the second antiferromagnetic layer in a region overlapping the bottom face of the groove is at least 10 Å

and at most 50 Å

.

21. The magnetic sensing element according to claim 19,

wherein a third antiferromagnetic layer is laminated between the second antiferromagnetic layer and free magnetic layer, and

one of a thickness of the second antiferromagnetic layer in a region overlapping the bottom face of the groove and a combined thickness of the second antiferromagnetic layer and third antiferromagnetic layer in the region overlapping the bottom face of the groove is at least 10 Å

and at most 50 Å

.

22. The magnetic sensing element according to claim 18, wherein a third antiferromagnetic layer is laminated between the second antiferromagnetic layer and free magnetic layer, and a bottom face of the groove is provided within the third antiferromagnetic layer.

23. The magnetic sensing element according to claim 22, wherein a thickness of the third antiferromagnetic layer in a region overlapping the bottom face of the groove is at least 10 Å

and at most 50 Å

.

24. The magnetic sensing element according to claim 18, wherein a second nonmagnetic layer comprising a precious metal is formed between the second antiferromagnetic layer and free magnetic layer and a bottom face of the groove is provided within the second nonmagnetic layer.

25. The magnetic sensing element according to claim 18, wherein a second nonmagnetic layer comprising one of Cr and Cu is formed between the second antiferromagnetic layer and free magnetic layer and a bottom face of the groove is provided within the second nonmagnetic layer.

26. The magnetic sensing element according to claim 18, wherein a ferromagnetic layer is formed one of between the second antiferromagnetic layer and free magnetic layer and between the second antiferromagnetic layer and nonmagnetic layer, and a bottom face of the groove is provided within the ferromagnetic layer.

27. The magnetic sensing element according to claim 18,

wherein a third antiferromagnetic layer is laminated between the second antiferromagnetic layer and free magnetic layer,

a second nonmagnetic layer comprising a precious metal is formed one of between the second antiferromagnetic layer and free magnetic layer and between the second antiferromagnetic layer and third antiferromagnetic layer, and

a bottom face of the groove is provided within the second nonmagnetic layer.

28. The magnetic sensing element according to claim 18,

wherein a third antiferromagnetic layer is laminated between the second antiferromagnetic layer and free magnetic layer,

a second nonmagnetic layer comprising one of Cr and Cu is formed one of between the second antiferromagnetic layer and free magnetic layer and between the second antiferromagnetic layer and third antiferromagnetic layer, and

a bottom face of the groove is provided within the second nonmagnetic layer.

29. The magnetic sensing element according to claim 17, wherein a bottom face of the groove is provided within the second antiferromagnetic layer.

30. The magnetic sensing element according to claim 29, wherein a thickness of the second antiferromagnetic layer in a region overlapping the bottom face of the groove is at least 10 Å

and at most 50 Å

.

31. The magnetic sensing element according to claim 29,

wherein a third antiferromagnetic layer is laminated between the second antiferromagnetic layer and free magnetic layer, and

one of a thickness of the second antiferromagnetic layer in a region overlapping the bottom face of the groove and a combined thickness of the second antiferromagnetic layer and third antiferromagnetic layer in the region overlapping the bottom face of the groove is at least 10 Å

and at most 50 Å

.

32. The magnetic sensing element according to claim 17, wherein a third antiferromagnetic layer is laminated between the second antiferromagnetic layer and free magnetic layer, and a bottom face of the groove is provided within the third antiferromagnetic layer.

33. The magnetic sensing element according to claim 32, wherein a thickness of the third antiferromagnetic layer in a region overlapping the bottom face of the groove has a thickness of at least 10 Å

and at most 50 Å

.

34. The magnetic sensing element according to claim 17, wherein a second nonmagnetic layer comprising a precious metal is formed between the second antiferromagnetic layer and free magnetic layer and a bottom face of the groove is provided within the second nonmagnetic layer.

35. The magnetic sensing element according to claim 17, wherein a second nonmagnetic layer comprising one of Cr and Cu is formed between the second antiferromagnetic layer and free magnetic layer and a bottom face of the groove is provided within the second nonmagnetic layer.

36. The magnetic sensing element according to claim 17, wherein a ferromagnetic layer is formed one of between the second antiferromagnetic layer and free magnetic layer and between the second antiferromagnetic layer and nonmagnetic layer, and a bottom face of the groove is provided within the ferromagnetic layer.

37. The magnetic sensing element according to claim 17,

wherein a third antiferromagnetic layer is laminated between the second antiferromagnetic layer and free magnetic layer,

a second nonmagnetic layer comprising a precious metal is formed one of between the second antiferromagnetic layer and free magnetic layer and between the second antiferromagnetic layer and third antiferromagnetic layer, and

a bottom face of the groove is provided within the second nonmagnetic layer.

38. The magnetic sensing element according to claim 17,

wherein a third antiferromagnetic layer is laminated between the second antiferromagnetic layer and free magnetic layer,

a second nonmagnetic layer comprising one of Cr and Cu is formed one of between the second antiferromagnetic layer and free magnetic layer and between the second antiferromagnetic layer and third antiferromagnetic layer, and

a bottom face of the groove is provided within the second nonmagnetic layer.

39. The magnetic sensing element according to claim 1, further comprising a second nonmagnetic layer comprising a precious metal formed between the second antiferromagnetic layer and free magnetic layer, the second nonmagnetic layer formed with a uniform thickness from a central region through both side regions.

40. The magnetic sensing element according to claim 1, wherein electrode layers are provided in the track width direction on both side regions of a second multilayer comprising the free magnetic layer, nonmagnetic layer and pinned magnetic layer, and a sense current flows in a direction parallel to a surface of each layer in the second multilayer.

41. The magnetic sensing element according to claim 40, wherein the nonmagnetic layer comprises a nonmagnetic conductive material.

42. The magnetic sensing element according to claim 1, wherein upper electrode layers and lower electrode layers are provided on and under the multilayer, respectively, comprising the free magnetic layer, nonmagnetic layer and pinned magnetic layer, and a sense current flows in a direction perpendicular to the surface of the multilayer.

43. The magnetic sensing element according to claim 42, wherein the nonmagnetic layer comprises a nonmagnetic conductive material.

44. The magnetic sensing element according to claim 42, wherein the nonmagnetic layer comprises an insulating material.

45. A magnetic sensing element having a multilayer comprising a first antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic material layer and a free magnetic layer laminated in this order,

a pair of second antiferromagnetic layers formed with a distance therebetween in a track width direction so as to be stacked at least on both side regions of the free magnetic layer in the track width direction,

said free magnetic layer including at least one of a Ni_aFe_b layer, a NiFeX layer, an amorphous Co alloy layer containing an amorphous Co based magnetic material, and a CoFeX layer,

wherein a and b in Ni_aFe_b represented by at % satisfy the relation of a>

80 with a+b=100,

wherein X in the NiFeX layer represents at least one element selected from Mn, Cu, Zn, Ti, Al, Ge, Si, Cr, V, Sn, Ir, Ru, Nb, Sb, W, Mo, Os and Ta,

wherein X in the CoFeX layer represents at least one element selected from Ti, Al, Mn, Si, V, Cr, Ta, Zn, Sb, Ge, Mo and W, and

wherein a third antiferromagnetic layer is laminated between the second antiferromagnetic layer and free magnetic layer.

46. The magnetic sensing element according to claim 45, wherein the third antiferromagnetic layer has a thickness of at least 10 Å

and at most 50 Å

.

47. A magnetic sensing element having a multilayer comprising a first antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic material layer and a free magnetic layer laminated in this order,

a pair of second antiferromagnetic layers formed with a distance therebetween in a track width direction so as to be stacked at least on both side regions of the free magnetic layer in the track width direction,

said free magnetic layer including at least one of a Ni_aFe_b layer, a NiFeX layer, an amorphous Co alloy layer containing an amorphous Co based magnetic material, and a CoFeX layer,

wherein a and b in Ni_aFe_b represented by at % satisfy the relation of a>

80 with a+b=100,

wherein X in the NiFeX layer represents at least one element selected from Mn, Cu, Zn, Ti, Al, Ge, Si, Cr, V, Sn, Ir, Ru, Nb, Sb, W, Mo, Os and Ta,

wherein X in the CoFeX layer represents at least one element selected from Ti, Al, Mn, Si, V, Cr, Ta, Zn, Sb, Ge, Mo and W,

wherein a second nonmagnetic layer comprising a precious metal is formed between the second antiferromagnetic layer and free magnetic layer, and

the second nonmagnetic layer has a smaller thickness at both side regions than a thickness at a central region.

48. The magnetic sensing element according to claim 47, wherein the second nonmagnetic layer comprises at least one of Ru, Rh, Pd, Ir, Os, Re, Pt and Au.

49. The magnetic sensing element according to claim 47, wherein the central region of the second nonmagnetic layer has a thickness of at least 3 Å

and at most 20 Å

.