Spin valve sensors with an oxide layer utilizing electron specular scattering effect

• US 6,556,390 B1
• Filed: 04/25/2000
• Issued: 04/29/2003
• Est. Priority Date: 10/28/1999
• Status: Expired due to Term

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Gao, Zheng, Chen, Jian, Mao, Sining, Murdock, Edward Stephens
• Primary Examiner(s): EVANS, JEFFERSON A
• Application Number:
  US09/558,253
• Time in Patent Office: 1,099 Days
• Field of Search: 360/324.1, 360/324.11, 360/324.12, 360/317
• US Class Current: 360/324.1
• 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: H01F 10/3259 Spin-exchange-coupled multilayers comprising at least a nanooxide layer [NOL], e.g. with a NOL spacer
• CPC Class Codes: H01F 10/3263 the exchange coupling being symmetric, e.g. for dual spin valve, e.g. NiO/Co/Cu/Co/Cu/Co/NiO
• 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

Abstract

The present invention comprises a magnetoresistive sensor including a cap layer, a free layer, a spacer layer, a pinned layer, an oxide layer, a pinning layer, a seed layer, and a substrate layer. The sensor consists of the cap layer adjacent the free layer. The free layer is adjacent to the spacer layer. The spacer layer is adjacent to the pinned layer. The pinned layer is adjacent to the oxide layer. The oxide layer is adjacent to the pinning layer. The pinning layer is adjacent to the seed layer and the seed layer is adjacent to the substrate. The present invention also comprises a method of manufacturing the magnetoresistive sensor including forming a layered structure. An electron specular scattering effect occurs at the oxide interface to achieve enhanced GMR responses while maintaining thermostability.

Claims

1. A magnetoresistive sensor comprising:

an oxide layer comprising opposing first and second surfaces;

a pinned layer comprising a first surface contacting the first surface of the oxide layer and a second surface contacting a first surface of a non-magnetic spacer;

a free magnetic layer comprising a first surface separated from the pinned layer by the non-magnetic spacer;

a pinning layer comprising a first surface separated from the pinned layer by the oxide layer; and

a seed layer comprising a first surface contacting a second surface of the pinning layer and a second surface contacting a first surface of a substrate.

2. The sensor of claim 1 further comprising a second pinned layer comprising a first surface contacting the second surface of the oxide layer and a second surface contacting the first surface of the pinning layer.

3. The sensor of claim 2 further comprising:

a second oxide layer comprising a first surface contacting the second surface of the free magnetic layer; and

a second surface contacting a first surface of a second free layer.

4. The sensor of claim 2 further comprising:

a second non-magnetic spacer comprising a first surface contacting a second surface of the free magnetic layer and a second surface contacting a first surface of a third pinned layer;

a second oxide layer comprising a first surface contacting a second surface of a third pinned layer and a second surface contacting a first surface of a forth pinned layer; and

a second pinning layer comprising a first surface contacting a second surface of the forth pinned layer.

5. The sensor of claim 1 further comprising:

a second pinned layer comprising a first surface contacting the second surface of the oxide layer and a second surface contacting a first surface of a Ru layer; and

a third pinned layer comprising a first surface contacting a second surface of the Ru layer and a second surface contacting the first surface of the pinning layer.

6. The sensor of claim 5 further comprising:

a second non-magnetic spacer comprising a first surface contacting a second surface of the free magnetic layer and a second surface contacting a first surface of a forth pinned layer;

a second oxide layer comprising a first surface contacting a second surface of the forth pinned layer and a second surface contacting a first surface of a fifth pinned layer;

a second Ru layer comprising a first surface contacting a second surface of the fifth pinned layer and a second surface contacting a first surface of a sixth pinned layer; and

a second pinning layer comprising a first surface contacting a second surface of the sixth pinned layer.

7. The sensor of claim 1 further comprising:

a second non-magnetic spacer comprising a first surface contacting a second surface of the free magnetic layer and a second surface contacting a first surface of a second pinned layer; and

a second oxide layer comprising a first surface contacting a second surface of the second pinned layer and a second surface contacting a first surface of a second pinning layer.

8. The sensor of claim 1 further comprising a cap layer comprising a first surface separated from the non-magnetic spacer by the free magnetic layer.

9. The sensor of claim 1 wherein the pinning layer comprises a material selected from the group consisting of NiMn and PtMn.

10. A method of manufacturing a magnetoresistive sensor comprising:

forming a layer structure comprising;

an oxide layer having opposing first and second surfaces;

a pinned layer comprising a first surface contacting the first surface of the oxide layer and a second surface contacting a first surface of a non-magnetic spacer;

a free magnetic layer comprising a first surface separated from the pinned layer by the non-magnetic spacer;

a pinning layer comprising a first surface separated from the pinned layer by the oxide layer; and

a seed layer comprising a first surface contacting a second surface of the pinning layer and a second surface contacting a first surface of a substrate.

11. The method of claim 10 wherein the layer structure further comprises a second pinned layer comprising a first surface contacting the second surface of the oxide layer and a second surface contacting the first surface of the pinning layer.

12. The method of claim 11 wherein the layer structure further comprises:

a second oxide layer comprising a first surface contacting the second surface of the free magnetic layer; and

a second surface contacting a first surface of a second free magnetic layer.

13. A method of claim 11 wherein the layer structure further comprises:

a second non-magnetic spacer comprising a first surface contacting a second surface of the free magnetic layer and a second surface contacting a first surface of a third pinned layer;

a second oxide layer comprising a first surface contacting a second surface of a third pinned layer and a second surface contacting a first surface of a forth pinned layer; and

a second pinning layer comprising a first surface contacting a second surface of the forth pinned layer.

14. The method of claim 10 wherein the layer structure further comprises:

a second pinned layer comprising a first surface contacting the second surface of the oxide layer and a second surface contacting a first surface of a Ru layer; and

a third pinned layer comprising a first surface contacting a second surface of the Ru layer and a second surface contacting the first surface of the pinning layer.

15. A method of claim 14 wherein the layer structure further comprises:

a second non-magnetic spacer comprising a first surface contacting a second surface of the free magnetic layer and a second surface contacting a first surface of a forth pinned layer;

a second oxide layer comprising a first surface contacting a second surface of the forth pinned layer and a second surface contacting a first surface of a fifth pinned layer;

a second Ru layer comprising a first surface contacting a second surface of the fifth pinned layer, and a second surface contacting a first surface of a sixth pinned layer; and

a second pinning layer comprising a first surface contacting a second surface of the sixth pinned layer.

16. A method of claim 10 wherein the layer structure further comprises:

a second non-magnetic spacer comprising a first surface contacting the second surface of the free magnetic layer and a second surface contacting a first surface of a second pinned layer; and

a second oxide layer comprising a first surface contacting a second surface of the second pinned layer and a second surface contacting a first surface of a second pinning layer.

17. A method of claim 10 wherein the layer structure further comprises a cap layer comprising a first surface separated from the non-magnetic spacer by the free non-magnetic layer.

18. A magnetoresistive sensor comprising:

a specular reflection layer comprising opposing first and second surfaces;

a pinned layer comprising a first surface contacting the first surface of the specular reflection layer and a second surface contacting a first surface of a non-magnetic spacer;

a free magnetic layer comprising a first surface separated from the pinned layer by the non-magnetic spacer;

a pinning layer comprising a first surface separated from the pinned layer by the specular reflection; and

a seed layer positioned between the pinning layer and a substrate layer.

19. The sensor of claim 18 further comprising a second pinned layer comprising a first surface contacting the second surface of the specular reflection layer and a second surface contacting the first surface of the pinning layer.

20. The sensor of claim 19 further comprising a second specular reflection layer comprising a first surface and a second surface, wherein the first surface is contacting the second surface of the free magnetic layer and the second surface is contacting a first surface of a second free layer.

21. The sensor of claim 19 further comprising:

a second non-magnetic spacer comprising a first surface contacting a second surface of the free magnetic layer and a second surface contacting a first surface of a third pinned layer;

a second specular reflection layer comprising a first surface contacting a second surface of a third pinned layer and a second surface contacting a first surface of a fourth pinned layer;

a second pinning layer comprising a first surface contacting a second surface fourth pinned layer.

22. The sensor of claim 18 further comprising:

a second pinned layer comprising a first surface contacting the second surface of the specular reflection layer and a second surface contacting a first surface of a Ru layer; and

a third pinned layer comprising a first surface contacting a second surface of the Ru layer and a second surface contacting the first surface of the pinning layer.

23. The sensor of claim 22 further comprising:

a second non-magnetic spacer comprising a first surface contacting a second of the free magnetic layer and a second surface contacting a first surface of a fourth pinned layer;

a second specular reflection layer comprising a first surface contacting a second surface of the fourth pinned layer and a second surface contacting a first surface of a fifth pinned layer;

a second Ru layer comprising a first surface contacting a second surface of the fifth pinned layer and a second surface contacting a first surface of a sixth pinned layer; and

a second pinning layer comprising a first surface contacting a second surface of the sixth pinned layer.

24. The sensor of claim 18 further comprising:

a second non-magnetic spacer comprising a first surface contacting a second surface of the free magnetic layer and a second surface contacting a first surface of a second pinned layer; and

a second specular reflection layer comprising a first surface contacting a second surface of the second pinned layer and a second surface contacting a first surface of a second pinning layer.

25. The sensor of claim 18 further comprising a cap layer comprising a first surface separated from the non-magnetic spacer by the free magnetic layer.

26. The sensor of claim 18 wherein the pinning layer comprises a material selected from the group consisting of NiMn and PtMn.