FeTa nano-oxide layer as a capping layer for enhancement of giant magnetoresistance in bottom spin valve structures

• US 7,262,941 B2
• Filed: 05/28/2004
• Issued: 08/28/2007
• Est. Priority Date: 01/16/2002
• Status: Expired due to Fees

• Current Assignee: Headway Technologies Incorporated (TDK Corporation)
• Original Assignee: Headway Technologies Incorporated (TDK Corporation)
• Inventors: Ju, Kochan, Li, Min, Horng, Cheng T., Sano, Masashi, Liao, Simon H., Noguchi, Kiyoshi
• Primary Examiner(s): Miller; Brian E.
• Application Number:
  US10/856,180
• Publication Number:
  US 20040223266A1
• Time in Patent Office: 1,187 Days
• Field of Search: 360/324.1, 360/324.12
• US Class Current: 360/324.12
• CPC Class Codes: B32B 15/01 all layers being exclusively metallic making layered metal workpieces by pressure cladding B23K20/22; making coatings with a metallic material characterised by its composition C23C30/00
• 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: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C22C 38/10 containing cobalt
• CPC Class Codes: C22C 38/12 containing tungsten, tantalum, molybdenum, vanadium, or niobium
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G11B 5/3163 Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers
• 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 10/3272 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 41/302 for applying spin-exchange-coupled multilayers, e.g. nanostructured superlattices spin-exchange-coupled multilayers H01F10/32
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: Y10T 29/49034 Treating to affect magnetic properties
• CPC Class Codes: Y10T 29/49044 Plural magnetic deposition layers
• CPC Class Codes: Y10T 29/49046 with etching or machining of magnetic material

Abstract

An NiCr seed layer based bottom spin valve sensor element having a synthetic antiferromagnet pinned (SyAP) layer and a capping layer comprising either a single specularly reflecting nano-oxide layer (NOL) or a bi-layer comprising a non-metallic layer and a specularly reflecting nano-oxide layer. As a result of their structure and the method of their fabrication, these elements have higher GMR ratios and lower resistances than elements of the prior art.

Claims

1. A bottom spin valve magnetoresistive sensor element comprising:

a substrate;

a magnetoresistive-property-enhancing seed layer formed on said substrate;

a pinning layer of antiferromagnetic material formed on said seed layer;

a synthetic antiferromagnetic pinned (SyAP) layer formed on said pinning layer, said SyAP layer further comprising;

a second antiparallel (AP2) pinned layer of ferromagnetic material formed on said pinning layer;

a non-magnetic coupling layer formed on said second antiparallel (AP2) pinned layer; and

a first antiparallel (AP1) pinned layer formed on said non-magnetic coupling layer to complete said SyAP layer;

a non-magnetic spacer layer formed on said first antiparallel (AP1) layer of said SyAP layer;

a ferromagnetic free layer formed on said non-magnetic spacer layer;

a non-magnetic material layer formed on said ferromagnetic free layer;

a specularly reflecting capping layer formed on said non-magnetic material layer, said capping layer comprising a layer of oxidized Fe₉₅Ta₅ or oxidized (Fe₆₅Co₃₅)₉₇V₃; and

said free layer being longitudinally magnetized and said pinned magnetic layers being magnetized transversely to said free layer.

2. The sensor element of claim 1 wherein said magnetoresistive-property-enhancing seed layer is a layer of either NiCr or NiFeCr deposited to a thickness of between approximately 30 and 70 angstroms.

3. The sensor element of claim 1 wherein the second antiparallel pinned layer (AP2) is a layer of ferromagnetic material chosen from the group consisting of CoFe NiFe and NiFeCo.

4. The sensor element of claim 3 wherein the second antiparallel pinned layer (AP2) is a layer of CoFe formed to a thickness of between approximately 10 and 25 angstroms.

5. The sensor element of claim 3 wherein the non-magnetic spacer layer is a layer of Cu of thickness approximately 18 angstroms.

6. The sensor element of claim 3 wherein the non-magnetic spacer layer is a layer of Cu of thickness approximately 19 angstroms.

7. The sensor element of claim 1 wherein the ferromagnetic free layer is a layer of ferromagnetic material chosen from the group consisting of CoFe, NiFe, CoFeNi and CoFe/NiFe.

8. The sensor element of claim 7 wherein the ferromagnetic free layer is a layer of CoFe formed to a thickness of between approximately 10 and 60 angstroms.

9. The sensor element of claim 1 wherein the non-magnetic material layer is a layer of non-magnetic material chosen from the group consisting of Cu, Ag, Au, Rh and Ru.

10. The sensor element of claim 9 wherein the non-magnetic material layer is a layer of Cu formed to a thickness of between approximately 0 and 20 angstroms.

11. The sensor element of claim 1 wherein the oxidized Fe₉₅Ta₅ specularly reflecting capping layer is between approximately 5 and 40 angstroms thickness.

12. The sensor element of claim 1 wherein the specularly reflecting capping layer of oxidized (Fe₆₅Co₃₅)₉₇V₃ is between approximately 5 and 40 angstroms thickness.

13. A bottom spin valve magnetoresistive sensor element comprising:

a substrate;

a magnetoresistive-property-enhancing seed layer formed on the substrate;

a pinning layer of antiferromagnetic material formed on said seed layer;

a synthetic antiferromagnetic pinned (SyAP) layer formed on said pinning layer, said SyAP layer further comprising;

a second antiparallel (AP2) pinned layer of ferromagnetic material formed as a triply laminated layer comprising a first and a second ferromagnetic layer separated by a first non-magnetic spacer layer on said pinning layer;

a non-magnetic coupling layer formed on said second antiparallel (AP2) pinned layer; and

a first antiparallel (AP1) pinned layer formed on said non-magnetic coupling layer to complete said SyAP layer;

a second non-magnetic spacer layer formed on said first antiparallel (AP1) layer of said SyAP layer;

a ferromagnetic free layer formed of CoFe to a thickness of approximately 20 angstroms on said non-magnetic spacer layer;

a capping layer of specularly reflecting material formed of oxidized Fe₉₅Ta₅ or oxidized (Fe₆Co₃₅)₉₇V₃ formed on said ferromagnetic free layer; and

said free layer being longitudinally magnetized and said pinned magnetic layers being magnetized transversely to said free layer.

14. The sensor of claim 13 wherein said magnetoresistive-property-enhancing seed layer is a layer of either NiCr or NiFeCr deposited to a thickness of between approximately 30 and 70 angstroms.

15. The sensor of claim 13 wherein said first and second ferromagnetic layers are layers of ferromagnetic material chosen from the group consisting of CoFe, NiFe and CoFeNi.

16. The sensor of claim 15 wherein said first and second ferromagnetic layers are layers of CoFe, wherein each layer is formed to a thickness of between approximately 5 and 15 angstroms.

17. The sensor of claim 13 wherein said first non-magnetic spacer layer is a layer of non-magnetic material chosen from the group consisting of Ta, NiCr and NiFeCr.

18. The sensor of claim 13 wherein said first non-magnetic spacer layer is a layer of Ta deposited to a thickness of between approximately 0.5 and 5 angstroms.

19. The sensor of claim 13 wherein said first antiparallel pinned layer (AP1) is a layer of ferromagnetic material chosen from the group consisting of CoFe, NiFe and CoFeNi.

20. The sensor of claim 19 wherein said first antiparallel pinned layer (AP1) is a layer of CoFe formed to a thickness of between approximately 10 and 30 angstroms.

21. The sensor of claim 20 wherein said non-magnetic spacer layer is a layer of Cu of thickness approximately 19 angstroms.

22. The sensor of claim 13 wherein said specularly reflecting capping layer of oxidized Fe₉₅Ta₅ is formed to a thickness of between approximately 5 and 40 angstroms.