Magnetoresistive element

• US 20040130431A1
• Filed: 12/10/2003
• Published: 07/08/2004
• Est. Priority Date: 04/24/2002
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Kawashima, Yoshio, Sugita, Yasunari, Odagawa, Akihiro, Matsukawa, Nozomu, Satomi, Mitsuo
• Granted Patent: US 6,861,940 B2
• Time in Patent Office: Days
• US Class Current: 338/32R
• 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: H01F 10/324 Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer
• CPC Class Codes: H01F 10/3254 the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
• CPC Class Codes: H01F 10/3268 the exchange coupling being asymmetric, e.g. by use of additional pinning, by using antiferromagnetic or ferromagnetic coupling interface, i.e. so-called spin-valve [SV] structure, e.g. NiFe/Cu/NiFe/FeMn
• CPC Class Codes: H01F 10/3272 by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets
• CPC Class Codes: H10N 50/85 Magnetic active materials

Abstract

A magnetoresistive element of the present invention includes a multilayer structure that includes a non-magnetic layer (3) and a pair of ferromagnetic layers (1, 2) stacked on both sides of the non-magnetic layer (3). A resistance value differs depending on a relative angle between the magnetization directions of the ferromagnetic layers (1, 2) at the interfaces with the non-magnetic layer (3). The composition of at least one of the ferromagnetic layers (1, 2) in a range of 2 nm from the interface with the non-magnetic layer (3) is expressed by (M_xO_y)_1-zZ_z, where Z is at least one element selected from the group consisting of Ru, Os, Rh, Ir, Pd, Pt, Cu, Ag, and Au, M is at least one element selected from the group consisting of elements other than Z and O and includes a ferromagnetic metal, and x, y, and z satisfy 0.33<y/x<1.33, 0<x, 0<y, and 0≦z≦0.4. This magnetoresistive element can have excellent heat resistance and magnetoresistance characteristics.

Claims

1. A magnetoresistive element comprising:

a multilayer structure comprising a non-magnetic layer and a pair of ferromagnetic layers stacked on both sides of the non-magnetic layer,

wherein a resistance value differs depending on a relative angle between magnetization directions of the ferromagnetic layers at interfaces with the non-magnetic layer, and

a composition of at least one of the ferromagnetic layers in a range of 2 nm from the interface with the non-magnetic layer is expressed by

(M_xO_y)_1-zZ_z

where Z is at least one element selected from the group consisting of Ru, Os, Rh, Ir, Pd, Pt, Cu, Ag, and Au, M is at least one element selected from the group consisting of elements other than Z and O and includes a ferromagnetic metal, and x, y, and z satisfy

0.33<

y/x<

1.33, 0<

x, 0<

y, and 0≦

z≦

0.4.

2. The magnetoresistive element according to claim 1, wherein z satisfies z>

0.

6. The magnetoresistive element according to claim 1, wherein M includes Fe.

8. The magnetoresistive element according to claim 6, wherein M is expressed by

Fe_pCo_qNi_r

where p, q, and r satisfy

p+q+r=1, 0.47≦

p≦

1, 0≦

q≦

0.4, and 0≦

r≦

0.4.

9. The magnetoresistive element according to claim 8, wherein p satisfies p>

0.5.

12. The magnetoresistive element according to claim 6, wherein M is expressed by

Fe_aX¹_bX²_c

where X¹ is at least one element selected from the group consisting of Co, Ni, Mn, Tc, Re, Zn, Cd, Hg, Be, Mg, Ca, Sr, Ba, and Ra, X² is at least one element selected from the group consisting of Li, Na, K, Rb, Cs, and Fr, and a, b, and c satisfy

a+b+c=1, 0.4<

a≦

1, 0≦

b/a≦

0.5, 0≦

c/a≦

0.25, and 0≦

(b+2c)/a<

0.5.

13. The magnetoresistive element according to claim 12, wherein a satisfies a>

0.5.

16. The magnetoresistive element according to claim 6, wherein M is expressed by

Fe_aX¹_bX²_cX³_dX⁴_eX⁵_f

where X¹ is at least one element selected from the group consisting of Co, Ni, Mn, Tc, Re, Zn, Cd, Hg, Be, Mg, Ca, Sr, Ba, and Ra, X² is at least one element selected from the group consisting of Li, Na, K, Rb, Cs, and Fr, X³ is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Sc, Y, lanthanide, actinide, Al, Ga, In, and Tl, X⁴ is at least one element selected from the group consisting of Si, Ge, Sn, Pb, As, Sb, and Bi, X⁵ is at least one element selected from the group consisting of B, C, N, P, and S, and a, b, c, d, e, and f satisfy

a+b+c+d+e+f=1, 0.4<

a≦

1, 0≦

b/a<

0.5, 0≦

c/a≦

0.25, 0≦

(b+2c)/a<

0.5, 0≦

d, 0≦

e, 0≦

d+e≦

0.3, and 0≦

f<

0.08.

17. The magnetoresistive element according to claim 16, wherein a satisfies a>

0.5.

20. The magnetoresistive element according to claim 1, wherein the ferromagnetic layers include a spinel-type compound.

22. The magnetoresistive element according to claim 1, further comprising an antiferromagnetic layer.

23. The magnetoresistive element according to claim 22, wherein the antiferromagnetic layer includes Mn.

24. The magnetoresistive element according to claim 23, wherein the antiferromagnetic layer includes at least one metal selected from the group consisting of PtMn, PdPtMn, IrMn, FeMn, NiMn, and RhMn.

25. The magnetoresistive element according to claim 22, wherein a distance between the antiferromagnetic layer and the non-magnetic layer is not less than 3 nm and not more than 50 nm.

30. The magnetoresistive element according to claim 1, wherein the non-magnetic layer is made of a conductive material.

32. The magnetoresistive element according to claim 1, wherein the non-magnetic layer is made of an insulating material.

34. The magnetoresistive element according to claim 1, obtained by heat treatment at not less than 300°

C.

3. A magnetoresistive element comprising:

a multilayer structure comprising a non-magnetic layer and a pair of ferromagnetic layers stacked on both sides of the non-magnetic layer,

wherein a resistance value differs depending on a relative angle between magnetization directions of the ferromagnetic layers at interfaces with the non-magnetic layer, and

a composition of at least one of the ferromagnetic layers in a range of 6 nm from the interface with the non-magnetic layer is expressed by

(M_x′

O_y′

)_1-z′

Z_z′

where Z is at least one element selected from the group consisting of Ru, Os, Rh, Ir, Pd, Pt, Cu, Ag, and Au, M is at least one element selected from the group consisting of elements other than Z and O and includes a ferromagnetic metal, and x′

, y′

, and z′

satisfy

0<

y′

/x′

<

1.33, 0<

x′

, 0<

y′

, and 0≦

z′

≦

0.4.

4. The magnetoresistive element according to claim 3, wherein the composition of at least one of the ferromagnetic layers in a range of 2 nm from the interface with the non-magnetic layer is expressed by

(M_x′

O_y′

)_1-z′

Z<sub>z′

.</sub>

5. The magnetoresistive element according to claim 3, wherein z′

satisfies z′

>

0.

7. The magnetoresistive element according to claim 3, wherein M includes Fe.

10. The magnetoresistive element according to claim 7, wherein M is expressed by

Fe_pCo_qNi_r

where p, q, and r satisfy

p+q+r=1, 0.47≦

p≦

1, 0≦

q≦

0.4, and 0≦

r≦

0.4.

11. The magnetoresistive element according to claim 10, wherein p satisfies p>

0.5.

14. The magnetoresistive element according to claim 7, wherein M is expressed by

Fe_aX¹_bX²_c

where X¹ is at least one element selected from the group consisting of Co, Ni, Mn, Tc, Re, Zn, Cd, Hg, Be, Mg, Ca, Sr, Ba, and Ra, X² is at least one element selected from the group consisting of Li, Na, K, Rb, Cs, and Fr, and a, b, and c satisfy

a+b+c=1, 0.4<

a≦

1, 0≦

b/a≦

0.5, 0≦

c/a≦

0.25, and 0≦

(b+2c)/a<

0.5.

15. The magnetoresistive element according to claim 14, wherein a satisfies a>

0.5.

18. The magnetoresistive element according to claim 7, where M is expressed by

Fe_aX¹_bX²_cX³_dX⁴_eX⁵_f

where X¹ is at least one element selected from the group consisting of Co, Ni, Mn, Tc, Re, Zn, Cd, Hg, Be, Mg, Ca, Sr, Ba, and Ra, X² is at least one element selected from the group consisting of Li, Na, K, Rb, Cs, and Fr, X³ is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Sc, Y, lanthanide, actinide, Al, Ga, In, and Tl, X⁴ is at least one element selected from the group consisting of Si, Ge, Sn, Pb, As, Sb, and Bi, X⁵ is at least one element selected from the group consisting of B, C, N, P, and S, and a, b, c, d, e, and f satisfy

a+b+c+d+e+f=1, 0.4≦

a≦

1, 0<

b/a<

0.5, 0≦

c/a≦

0.25, 0≦

(b+2c)/a<

0.5, 0≦

d, 0≦

e, 0≦

d+e≦

0.3, and 0≦

f <

0.08.

19. The magnetoresistive element according to claim 18, wherein a satisfies a>

0.5.

21. The magnetoresistive element according to claim 3, wherein the ferromagnetic layers include a spinel-type compound.

26. The magnetoresistive element according to claim 3, further comprising an antiferromagnetic layer.

27. The magnetoresistive element according to claim 26, wherein the antiferromagnetic layer includes Mn.

28. The magnetoresistive element according to claim 27, wherein the antiferromagnetic layer includes at least one metal selected from the group consisting of PtMn, PdPtMn, IrMn, FeMn, NiMn, and RhMn.

29. The magnetoresistive element according to claim 26, wherein a distance between the antiferromagnetic layer and the non-magnetic layer is not less than 3 nm and not more than 50 nm.

31. The magnetoresistive element according to claim 3, wherein the non-magnetic layer is made of a conductive material.

33. The magnetoresistive element according to claim 3, wherein the non-magnetic layer is made of an insulating material.

35. The magnetoresistive element according to claim 3, obtained by heat treatment at not less than 300°

C.