Magnetic sensing element comprising antiferromagnetic layer laminated on free magnetic layer

• US 20030184925A1
• Filed: 03/27/2003
• Published: 10/02/2003
• Est. Priority Date: 03/29/2002
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Ishizone, Masahiko, Hasegawa, Naoya, Umetsu, Eiji, Koike, Fumihito
• Granted Patent: US 6,995,961 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 5/3903 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 is facilitated by using a layer comprising a magnetic material having a small exchange stiffness constant such as the NiFe layer comprising the Ni_aFe_b alloy (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,

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

said free magnetic layer comprising at least one of a NiFe layer with a composition of NiaFeb, a NiFeX layer, an amorphous Co alloy layer comprising 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, and

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.

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

m or less.

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

m or less.

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

m or less.

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 NiFe layer with a composition of Ni_aFe_b and NiFeX layer,

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

80 with a+b=100, and

X in the NiFeX layer representing 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.

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,

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

7. The magnetic sensing element according to claim 6,

wherein a magnetic layer having a smaller resistivity than the resistivity of the amorphous Co alloy layer is laminated under the amorphous Co alloy layer, or a magnetic layer having a smaller resistivity than the CoFeX layer is laminated under the CoFeX layer,

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

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

X in the NiFeX layer representing 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.

9. The magnetic sensing element according to claim 1,

wherein the free magnetic layer comprises a (Co_xFe_y)_eCr_f layer as the uppermost layer or lowermost layer closest to the second antiferromagnetic layer,

x and y represented by an at % ratio of Co to Fe satisfying the relation of x+y=1, and

e and f represented by at % satisfying the relations of 0<

f<

20 and e+f=100.

10. The magnetic sensing element according to claim 9,

wherein the free magnetic layer comprises a (Co_xFe_y)_eCr_f layer as the uppermost layer or the lowermost layer

x and y represented by an at % ratio of Co to Fe satisfying the relation of x+y=1, and

e and f represented by at % satisfying the relations of 5<

f<

15 and e+f=100.

11. The magnetic sensing element according to claim 9,

wherein the (Co_xFe_y)_eCr_f layer has a thickness of 2 Å

or more and 10 Å

or less.

12. The magnetic sensing element according to claim 11,

wherein the (Co_xFe_y)_eCr_f layer has a thickness of 3 Å

or more and 6 Å

or less.

13. The magnetic sensing element according to claim 10,

wherein the (Co_xFe_y)_eCr_f layer has a thickness of 2 Å

or more and 10 Å

or less.

14. The magnetic sensing element according to claim 13,

wherein the (Co_xFe_y)_eCr_f layer has a thickness of 3 Å

or more and 6 Å

or less.

15. The magnetic sensing element according to claim 1,

wherein exchange stiffness constants of the magnetic materials constituting the NiFe layer with a composition of Ni_aFe_b, NiFeX layer, amorphous Co alloy layer comprising the amorphous Co based alloy, and CoFeX layer to be used for the free magnetic layer are smaller than the exchange stiffness constant of a magnetic material represented by a composition formula of Ni₈₀Fe₂₀,

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

80 with a+b=100,

X in the NiFeX layer representing 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, and

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

16. The magnetic sensing element according to claim 1,

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

17. The magnetic sensing element according to claim 16,

wherein the third antiferromagnetic layer has a thickness of 10 Å

or more and 50 Å

or less.

18. The magnetic sensing element according to claim 1,

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

19. The magnetic sensing element according to claim 18,

wherein the nonmagnetic layer comprises at least one of Ru, Rh, Pd, Ir, Os, Re, Pt and Au.

20. The magnetic sensing element according to claim 1,

wherein a nonmagnetic layer comprising Cr or Cu is formed between the second antiferromagnetic layer and free magnetic layer, or between the second antiferromagnetic layer and third antiferromagnetic layer.

21. The magnetic sensing element according to claim 1,

wherein a ferromagnetic layer is formed between the second antiferromagnetic layer and free magnetic layer, or between the second antiferromagnetic layer and nonmagnetic layer.

22. The magnetic sensing element according to claim 1,

wherein the surface of the second antiferromagnetic layer comprises an opening, and a groove having a prescribed width is formed in the track width direction.

23. The magnetic sensing element according to claim 22,

wherein the side face of the groove is perpendicular to the surface of the second antiferromagnetic layer.

24. The magnetic sensing element according to claim 22,

wherein the bottom face of the groove is provided within the second antiferromagnetic layer.

25. The magnetic sensing element according to claim 24,

wherein the thickness of the second antiferromagnetic layer in the region overlapping the bottom face of the groove, or the combined thickness of the second antiferromagnetic layer and third antiferromagnetic layer in the region overlapping the bottom face of the groove is 10 Å

or more and 50 Å

or less.

26. The magnetic sensing element according to claim 22,

wherein the third antiferromagnetic layer is laminated between the second antiferromagnetic layer and free magnetic layer, and the bottom face of the groove is provided within the third antiferromagnetic layer.

27. The magnetic sensing element according to claim 26,

wherein the thickness of the third antiferromagnetic layer in the region overlapping the bottom face of the groove has a thickness of 10 Å

or more and 50 Å

or less.

28. The magnetic sensing element according to claim 22,

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

the bottom face of the groove being provided within the nonmagnetic layer.

29. The magnetic sensing element according to claim 22,

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

the bottom face of the groove being provided within the nonmagnetic layer.

30. The magnetic sensing element according to claim 22,

wherein an antiferromagnetic layer is formed between the second antiferromagnetic layer and free magnetic layer, or between the second antiferromagnetic layer and nonmagnetic layer,

the bottom face of the groove being provided within the ferromagnetic layer.

31. The magnetic sensing element according to claim 23,

wherein the bottom face of the groove is provided within the second antiferromagnetic layer.

32. The magnetic sensing element according to claim 31,

wherein the thickness of the second antiferromagnetic layer in the region overlapping the bottom face of the groove, or the combined thickness of the second antiferromagnetic layer and third antiferromagnetic layer in the region overlapping the bottom face of the groove is 10 Å

or more and 50 Å

or less.

33. The magnetic sensing element according to claim 23,

wherein a third antiferromagnetic layer is laminated between the second antiferromagnetic layer and free magnetic layer, and the bottom face of the groove is provided within the third antiferromagnetic layer.

34. The magnetic sensing element according to claim 33,

wherein the thickness of the third antiferromagnetic layer in the region overlapping the bottom face of the groove is 10 Å

or more and 50 Å

or less.

35. The magnetic sensing element according to claim 23,

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

the bottom face of the groove being provided within the nonmagnetic layer.

36. The magnetic sensing element according to claim 23,

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

the bottom face of the groove being provided within the nonmagnetic layer.

37. The magnetic sensing element according to claim 23,

wherein a ferromagnetic layer is formed between the second antiferromagnetic layer and free magnetic layer, or between the second antiferromagnetic layer and nonmagnetic layer,

the bottom face of the groove being provided within the ferromagnetic layer.

38. The magnetic sensing element according to claim 18,

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

39. The magnetic sensing element according to claim 38,

wherein the central region of the nonmagnetic layer is formed with a thickness of 3 Å

or more and 20 Å

or less.

40. The magnetic sensing element according to claim 18,

wherein the nonmagnetic layer is formed with a uniform thickness from the central region through both side regions.

41. The magnetic sensing element according to claim 1,

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

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 the direction perpendicular to the surface of the multilayer.

43. The magnetic sensing element according to claim 41,

wherein the nonmagnetic layer comprises a nonmagnetic conductive material.

44. The magnetic sensing element according to claim 42,

wherein the nonmagnetic layer comprises a nonmagnetic conductive material.

45. The magnetic sensing element according to claim 42,

wherein the nonmagnetic layer comprises an insulating material.