GMR design with nano oxide layer in the second anti-parallel pinned layer

• US 6,452,763 B1
• Filed: 06/06/2000
• Issued: 09/17/2002
• Est. Priority Date: 06/06/2000
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Gill, Hardayal Singh
• Primary Examiner(s): Tupper, Robert S.
• Assistant Examiner(s): Watko, Julie Anne
• Application Number:
  US09/588,253
• Time in Patent Office: 833 Days
• Field of Search: 360/324.11, 360/324.1, 360/324, 360/313, 360/110, 360/126
• US Class Current: 360/324.11
• 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: 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: H01F 10/3295 Spin-exchange coupled multilayers wherein the magnetic pinned or free layers are laminated without anti-parallel coupling within the pinned and free layers

Abstract

A high GMR coefficient for a spin valve sensor is achieved through the addition of one or more nano oxide layers in the second anti-parallel (AP) pinned layer of the pinned section of a spin valve sensor. The improvement occurs through increases in the GMR coefficient and magnetic stability of the spin valve sensor. The new second anti-parallel AP-pinned layer is formed with a plurality of layers of a magnetized metal separated by nano oxide layers. The metal layer(s) preferably comprise CoFe and the nano oxide layers preferably comprise of CoFeO. A PtMn antiferromagnetic layer and a CoFe first AP-pinned layer may also be used.

Claims

1. A spin valve sensor, comprising;

a substrate;

a seed layer formed on the substrate;

an antiferromagnetic (AFM) layer formed to a side of the seed layer;

a first anti-parallel (AP)-pinned layer formed to a side of the AFM layer;

a second anti-parallel (AP)-pinned layer comprising a plurality of thin laminate layers including at least one laminated oxide layer, the second AP-pinned layer separated from the first AP-pinned layer by an anti-parallel coupling (APC); and

a free layer, the first and second AP-pinned layers separated from the free layer by a spacer layer.

2. The spin valve sensor of claim 1, wherein the second anti-parallel (AP)-pinned layer comprises Co in a range of between about 45 and 55 percent and Fe in a range of between about 10 and 20 percent and Oxygen in a range of between about 30 and 40 percent.

3. The spin valve sensor of claim 1, wherein the second AP-pinned layer has a thickness in a range of between about 15 Å

and about 30 Å

.

4. The spin valve sensor of claim 1, wherein the second anti-parallel AP-pinned layer comprises a plurality of metal laminate layers separated by the at least one laminated oxide layer.

5. The spin valve sensor of claim 4, wherein the metal laminate layers comprise Co.

6. The spin valve sensor of claim 4, wherein the metal laminate layers comprise CoFe.

7. The spin valve sensor of claim 4, wherein the at least one laminated oxide layer comprises CoFeO.

8. The spin valve sensor of claim 1, wherein the AFM layer comprises PtMn.

9. A spin valve sensor, comprising;

a substrate;

a seed layer formed on the substrate and containing a face centered cubic material forming a (111) crystallographic plane substantially parallel to the substrate;

an antiferromagnetic (AFM) layer comprising PtMn, formed to a side of the seed layer;

a first anti-parallel AP-pinned layer comprising Co or CoFe, formed to a side of the AFM layer;

a second anti-parallel AP-pinned layer comprising a plurality of thin laminate layers including at least one laminated oxide layer, the second AP-pinned layer separated from the first AP-pinned layer by an anti-parallel coupling (APC); and

a free layer, the first and second AP-pinned layers separated from the free layer by a spacer layer.

10. The spin valve sensor of claim 9, wherein the second anti-parallel AP-pinned layer comprises about 50 percent Co and about 10 to 20 percent Fe and about 30 to 40 percent Oxygen.

11. The spin valve sensor of claim 10, wherein the second anti-parallel AP-pinned layer has a thickness of between about 15 Å

and 30 Å

.

12. The spin valve sensor of claim 11, wherein the second anti-parallel AP-pinned layer comprises a plurality of metal laminate layers separated by the at least one laminated oxide layer, wherein the metal laminate layers comprise CoFe.

13. The spin valve sensor of claim 12, wherein the at least one laminated oxide layer comprises CoFeO.

14. A disk drive system, comprising;

a spin valve sensor comprising;

a substrate;

a seed layer formed on the substrate;

an antiferromagnetic (AFM) layer formed to a side of the seed layer;

a first anti-parallel AP-pinned layer formed to a side of the AFM layer;

a second anti-parallel AP-pinned layer comprising a plurality of thin laminate layers including at least one laminated oxide layer, the second AP-pinned layer separated from the first AP-pinned layer by an anti-parallel coupling (APC); and

a free layer, the first and second AP-pinned layers and the free layer separated by a spacer layer;

an actuator for moving the spin valve sensor across a magnetic recording disk so the spin valve sensor may access different regions of magnetically recorded data on the magnetic recording disk; and

a detector coupled to the spin valve sensor for detecting changes in resistance of the sensor caused by rotation of a magnetization axis of the free ferrromagnetic layer relative to a fixed magnetization of the AP pinned layer in response to magnetic fields from the magnetically recorded data.

15. The disk drive system of claim 14, wherein the second AP-pinned layer has a thickness in a range of between about 15 Å

and about 30 Å

.

16. The spin valve sensor of claim 15, wherein the AFM layer comprises PtMn.

17. The disk drive system of claim 14 wherein the second anti-parallel AP-pinned layer comprises a plurality of metal laminate layers separated by the at least one laminated oxide layer.

18. The disk drive system of claim 17, wherein the metal laminate layers comprise Co.

19. The spin valve sensor of claim 17, wherein the metal laminate layers comprise CoFe.

20. The spin valve sensor of claim 17, wherein the at least one laminated oxide layer comprises CoFeO.