Magnetoresistive device, magnetoresistive head and magnetic recording-reproducing apparatus

• US 7,223,485 B2
• Filed: 03/07/2005
• Issued: 05/29/2007
• Est. Priority Date: 02/01/2001
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Yoshikawa, Masatoshi, Yuasa, Hiromi, Sahashi, Masashi, Iwasaki, Hitoshi, Kamiguchi, Yuzo
• Primary Examiner(s): MONSHIPOURI, MARYAM
• Application Number:
  US11/072,270
• Publication Number:
  US 20050152077A1
• Time in Patent Office: 813 Days
• Field of Search: None
• US Class Current: 428/812
• 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 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 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 5/3906 Details related to the use of magnetic thin film layers or to their effects
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• 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 10/3268 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: H10N 50/85 Magnetic active materials
• CPC Class Codes: Y10T 428/1107 Magnetoresistive
• CPC Class Codes: Y10T 428/1121 Multilayer
• CPC Class Codes: Y10T 428/1129 Super lattice [e.g., giant magneto resistance [GMR] or colossal magneto resistance [CMR], etc.]
• CPC Class Codes: Y10T 428/1143 with defined structural feature
• CPC Class Codes: Y10T 428/115 Magnetic layer composition
• CPC Class Codes: Y10T 428/1171 with defined laminate structural detail
• CPC Class Codes: Y10T 428/1193 with interlaminar component [e.g., adhesion layer, etc.]
• CPC Class Codes: Y10T 428/12465 having magnetic properties, or preformed fiber orientation coordinate with shape
• CPC Class Codes: Y10T 428/12868 Group IB metal-base component alternative to platinum group metal-base component [e.g., precious metal, etc.]
• CPC Class Codes: Y10T 428/12917 Next to Fe-base component
• CPC Class Codes: Y10T 428/12951 : Fe-base component
• CPC Class Codes: Y10T 428/265 : 1 mil or less
• CPC Class Codes: Y10T 428/32 : Composite [nonstructural laminate] of inorganic material having metal-compound-containing layer and having defined magnetic layer

Abstract

A magnetoresistive device includes a magnetization pinned layer, a magnetization free layer, a nonmagnetic intermediate layer formed between the magnetization pinned layer and the magnetization free layer, and electrodes allowing a sense current to flow in a direction substantially perpendicular to the plane of the stack including the magnetization pinned layer, the nonmagnetic intermediate layer and the magnetization free layer. At least one of the magnetization pinned layer and the magnetization free layer is substantially formed of a binary or ternary alloy represented by the formula Fe_aCo_bNi_c (where a+b+c=100 at %, and a≦75 at %, b≦75 at %, and c≦63 at %), or formed of an alloy having a body-centered cubic crystal structure.

Claims

1. A magnetoresistive device, comprising:

a magnetization pinned layer of which magnetization direction is substantially pinned to one direction;

a magnetization free layer of which magnetization direction is changed in accordance with an external magnetic field;

a nonmagnetic intermediate layer formed between the magnetization pinned layer and the magnetization free layer; and

electrodes allowing a sense current to flow in a direction substantially perpendicular to the plane of the stack including the magnetization pinned layer, the nonmagnetic intermediate layer and the magnetization free layer,

at least one of the magnetization pinned layer and the magnetization free layer comprising a ferromagnetic layer, the ferromagnetic layer is substantially formed of an alloy represented by the general formula (A) given below;

Fe_100-aCo_a 

 

(A)

where 10 at %≦

a≦

20 at %;

and the alloy having a body-centered cubic crystal structure.

2. The magnetoresistive device according to claim 1, wherein the at least one of the magnetization pinned layer and the magnetization free layer comprises a laminate structure comprising a plurality of the ferromagnetic layers and an insert layer formed between the plurality of the ferromagnetic layers, the insert layer is formed of at least one element selected from the group consisting of Cr, V, Ta, Nb, Sc, Ti, Mn, Cu, Zn, Ga, Ge, Zr, Hf, Y, Tc, Re, Ru, Rh, Ir, Pd, Pt, Ag, Au, B, Al, In, C, Si, Sn, Ca, Sr, Ba, O, N and F, and having a thickness falling within a range of between 0.03 nm and 1 nm.

3. The magnetoresistive device according to claim 2, wherein the insert layer is formed of Zn, Ti, Mn, Cu, Hf, Ga, Ge or Zr.

4. A magnetic head comprising the magnetoresistive device according to claim 1.

5. A magnetic recording-reproducing apparatus, comprising a magnetic recording medium, and the magnetoresistive device according to claim 1.

6. The magnetoresistive device according to claim 1, wherein a thickness of the magnetization pinned layer ranges from 0.5 nm to 3.5 nm.

7. The magnetoresistive device according to claim 1, wherein both of the magnetization pinned layer and the magnetization free layer comprise the ferromagnetic layer substantially formed of the alloy represented by the general formula (A).

8. The magnetoresistive device according to claim 1, the stack further comprises an antiferromagnetic layer arranged on the magnetization pinned layer.

9. The magnetoresistive device according to claim 8, wherein one of the electrodes is a lower electrode and other electrode is an upper electrode arranged under and over the stack including the antiferromagnetic layer, the magnetization pinned layer, the nonmagnetic intermediate layer and the magnetization free layer, respectively.

10. A magnetoresistive device, comprising:

a magnetization pinned layer of which magnetization direction is substantially pinned to one direction;

a magnetization free layer of which magnetization direction is changed in accordance with an external magnetic field;

a nonmagnetic intermediate layer formed between the magnetization pinned layer and the magnetization free layer; and

electrodes allowing a sense current to flow in a direction substantially perpendicular to the plane of the stack including the magnetization pinned layer, the nonmagnetic intermediate layer and the magnetization free layer,

at least one of the magnetization pinned layer and the magnetization free layer comprising a ferromagnetic layer, the ferromagnetic layer is substantially formed of an alloy represented by general formula (A) given below;

(Fe_(100-a)/100Co_a/100)_100-xM_x 

 

(A)

where 10 at %≦

a≦

20 at %;

0.1 at %≦

x≦

20 at %, and M is at least one element selected from the group consisting of Mn, Cu, Re, Ru, Pd, Pt, Ag, Au and Al;

and the alloy having a body-centered cubic crystal structure.

11. The magnetoresistive device according to claim 10, wherein the at least one of the magnetization pinned layer and the magnetization free layer comprises a laminate structure comprising a plurality of the ferromagnetic layers and an insert layer formed between the plurality of the ferromagnetic layers, the insert layer is formed of at least one element selected from the group consisting of Cr, V, Ta, Nb, Sc, Ti, Mn, Cu, Zn, Ga, Ge, Zr, Hf, Y, Tc, Re, Ru, Rh, Ir, Pd, Pt, Ag, Au, B, Al, In, C, Si, Sn, Ca, Sr, Ba, O, N and F, and having a thickness falling within a range of between 0.03 nm and 1 nm.

12. The magnetoresistive device according to claim 11, wherein the insert layer is formed of Zn, Ti, Mn, Cu, Hf, Ga, Ge or Zr.

13. A magnetic head comprising the magnetoresistive device according to claim 10.

14. A magnetic recording-reproducing apparatus, comprising a magnetic recording medium, and the magnetoresistive device according to claim 10.

15. The magnetoresistive device according to claim 10, wherein a thickness of the magnetization pinned layer ranges from 0.5 nm to 3.5 nm.

16. The magnetoresistive device according to claim 10, wherein both of the magnetization pinned layer and the magnetization free layer comprise the ferromagnetic layer substantially formed of the alloy represented by the general formula (A).

17. The magnetoresistive device according to claim 10, the stack further comprises an antiferromagnetic layer arranged on the magnetization pinned layer.

18. The magnetoresistive device according to claim 17, wherein one of the electrodes is a lower electrode and other electrode is an upper electrode arranged under and over the stack including the antiferromagnetic layer, the magnetization pinned layer, the nonmagnetic intermediate layer and the magnetization free layer, respectively.