Method and apparatus for improved pinning strength for self-pinned giant magnetoresistive heads

• US 6,801,412 B2
• Filed: 04/19/2002
• Issued: 10/05/2004
• Est. Priority Date: 04/19/2002
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Gill, Hardayal Singh
• Primary Examiner(s): EVANS, JEFFERSON A
• Application Number:
  US10/126,149
• Publication Number:
  US 20030197985A1
• Time in Patent Office: 900 Days
• Field of Search: 360/317, 360/324.1, 360/324.11, 360/324.12, 360/324.2
• 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 2005/0008 Magnetic conditionning of heads, e.g. biasing
• CPC Class Codes: G11B 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• 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 5/3932 Magnetic biasing films

Abstract

A Giant Magneto-Resistive (GMR) sensor (800) provides increased GMR effect through the use of composite laminate structure (870) as the second of two self-pinned layers of Anti-Parallel (AP) self-pinned layer 865. A positive magnetostrictive material forms the embedded layer (820) of AP pinned layer (865) to increase the perpendicular to Air Bearing Surface (ABS) intrinsic anisotropy field (H_k). The embedded layer (820) of AP pinned layer (865) has no effect on the GMR stack texture, since outer ferromagnetic layers (815 and 825) are provided to control the GMR stack texture.

Claims

1. A method of forming a spin valve sensor, comprising:

forming a first pinned layer having a first magnetic orientation on a substrate, the method of forming the first pinned layer includes embedding an inner ferromagnetic layer between first and second ferromagnetic layers, wherein the inner layer provides a greater positive magnetostrictive coefficient in relation to the first and second ferromagnetic layers; and

depositing a second pinned layer having a second magnetic orientation above the first pinned layer, wherein the first and second magnetic orientations are self-biased anti-parallel in relation to one another.

2. The method of claim 1, wherein the embedded inner layer is composed of a greater concentration of iron in reference to the first and second ferromagnetic layers.

3. The method of claim 2, wherein the embedded inner layer comprises a concentration of iron ranging from 30 to 50 percent.

4. The method of claim 1, wherein a thickness of the embedded layer is less than a thickness of the first and second ferromagnetic layers.

5. The method of claim 4, wherein the thickness of the embedded layer ranges from between 5 to 10 angstroms less than the thickness of the first and second ferromagnetic layers.

6. The method of claim 1 further comprising:

depositing an anti-parallel coupling layer between the first and second pinned layers;

depositing a conducting spacer layer above the second pinned layer; and

depositing a free layer above the spacer layer, a magnetic orientation of the free layer being responsive to an external signal field.

7. The method of claim 6, wherein the magnetic orientation of the free layer is substantially perpendicular to the magnetic orientation of the second pinned layer in the absence of a signal field.

8. A spin valve sensor comprising:

a first pinned layer having a first magnetic orientation, the first pinned layer comprising;

a first ferromagnetic layer;

a second ferromagnetic layer disposed above the first ferromagnetic layer; and

an inner ferromagnetic layer embedded between the first and second ferromagnetic layers, the inner ferromagnetic layer having a greater positive magnetostrictive coefficient in relation to the first and second ferromagnetic layers; and

a second pinned layer having a second magnetic orientation, wherein the first and second magnetic orientations are self-biased anti-parallel in relation to one another.

9. The spin valve sensor of claim 8, wherein the embedded inner layer is composed of a greater concentration of iron in reference to the first and second ferromagnetic layers.

10. The spin valve sensor of claim 9, wherein the embedded inner layer comprises a concentration of iron ranging from 30 to 50 percent.

11. The spin valve sensor of claim 8, wherein a thickness of the embedded layer is less than a thickness of the first and second ferromagnetic layers.

12. The spin valve sensor of claim 11, wherein the thickness of the embedded layer ranges from between 5 to 10 angstroms less than the thickness of the first and second ferromagnetic layers.

13. The spin valve sensor of claim 8 further comprising:

an anti-parallel coupling layer deposited between the first and second pinned layers;

a conducting spacer layer deposited above the second pinned layer; and

a free layer deposited above the spacer layer, a magnetic orientation of the free layer being responsive to an external signal field.

14. The spin valve sensor of claim 13, wherein the magnetic orientation of the free layer is substantially perpendicular to the magnetic orientation of the second pinned layer in the absence of a signal field.

15. A magnetic storage system, comprising:

a magnetic recording medium;

a spin valve sensor disposed proximate to the recording medium, the spin valve sensor, comprising

a first pinned layer having a first magnetic orientation, the first pinned layer comprising;

a first ferromagnetic layer;

a second ferromagnetic layer disposed above the first ferromagnetic layer; and

an inner ferromagnetic layer embedded between the first and second ferromagnetic layers, the inner ferromagnetic layer having a greater positive magnetostrictive coefficient in relation to the first and second ferromagnetic layers; and

a second pinned layer having a second magnetic orientation, wherein the first and second magnetic orientations are self-biased anti-parallel in relation to one another.

16. The magnetic storage system of claim 15, wherein the embedded inner layer is composed of a greater concentration of iron in reference to the first and second ferromagnetic layers.

17. The magnetic storage system of claim 16, wherein the embedded inner layer comprises a concentration of iron ranging from 30 to 50 percent.

18. The magnetic storage system of claim 15, wherein a thickness of the embedded layer is less than a thickness of the first and second ferromagnetic layers.

19. The magnetic storage system of claim 18, wherein the thickness of the embedded layer ranges from between 5 to 10 angstroms less than the thickness of the first and second ferromagnetic layers.

20. The magnetic storage system of claim 15 further comprising:

an anti-parallel coupling layer deposited between the first and second pinned layers;

a conducting spacer layer deposited above the second pinned layer; and

a free layer deposited above the spacer layer, a magnetic orientation of the free layer being responsive to an external signal field.

21. The magnetic storage system of claim 20, wherein the magnetic orientation of the free layer is substantially perpendicular to the magnetic orientation of the second pinned layer in the absence of a signal field.