Method and apparatus for providing a dual current-perpendicular-to-plane (CPP) GMR sensor with improved top pinning

1. A dual current-perpendicular-to-plane (CPP) GMR sensor, comprising:

a first magnetic shield formed of an electrically conductive and magnetically shielding material;

a second magnetic shield formed of an electrically conductive and magnetically shielding material, the first and the second magnetic shields disposed to define a read gap therebetween;

a spin valve structure disposed between the first and second magnetic shields, the spin valve structure including a dual spin valve arrangement, the dual spin valve arrangement having a top and bottom spin self pinned layer and a free ferromagnetic layers disposed therebetween; and

a biasing layer disposed adjacent only the top self pinned layer in a passive region for pinning the top self pinned layer.

2. The dual CPP GMR sensor of claim 1 further comprising:

a hard bias layer separate and distinct from the biasing layer formed proximate the bottom self-pinned layer in a passive region for biasing the bottom self-pinned layer;

a first metal oxide layer disposed between the biasing layer and the hard bias layer for providing an insulation layer to the hard bias layer; and

a second metal oxide layer formed above the biasing layer.

3. The dual CPP GMR sensor of claim 2 , wherein the metal oxide layers further comprises NiO.

4. The dual CPP GMR sensor of claim 2 further comprises a ferromagnetic layer disposed over the second metal oxide layer and the self-pinned layer, wherein the second metal oxide layer removes exchange coupling to the hard bias layer.

5. The dual CPP GMR sensor of claim 4 further comprising a Ta layer formed between the ferromagnetic layer and the second shield.

6. The dual CPP GMR sensor of claim 5 , wherein the ferromagnetic layer comprises NiFe.

7. The dual CPP GMR sensor of claim 1 further comprising a first and second metal oxide layer formed under and above the biasing layer.

8. The dual CPP GMR sensor of claim 7 , wherein the metal oxide layers further comprises NiO.

9. The dual CPP GMR sensor of claim 8 further comprises a ferromagnetic layer disposed below the second shield and over the second metal oxide layer and the self-pinned layer, wherein the second metal oxide layer removes exchange coupling to the hard bias layer.

10. The dual CPP GMR sensor of claim 9 further comprising a Ta layer formed between the ferromagnetic layer and the second shield.

11. The dual CPP GMR sensor of claim 9 , wherein the ferromagnetic layer comprises NiFe.

12. The dual CPP GMR sensor of claim 1 , wherein the first and second shields function as electrodes for supplying current to the spin valve structure.

13. The dual CPP GMR sensor of claim 1 , wherein the biasing layer comprises a layer of alpha-Fe 2 O 3 , the layer of alpha-Fe 2 O 3 pinning the top self-pinned layer.

14. The dual CPP GMR sensor of claim 13 , wherein the layer of alpha-Fe 2 O 3 pins the top portion of the top self-pinned layer by providing higher coercivity (H C ) to the top self-pinned layer.

15. A magnetic storage system, comprising:

a magnetic storage medium having a plurality of tracks for recording of data; and

a dual CPP GMR sensor maintained in a closely spaced position relative to the magnetic storage medium during relative motion between the magnetic transducer and the magnetic storage medium, the dual CPP GMR sensor further comprising:

a first magnetic shield formed of an electrically conductive and magnetically shielding material;

a second magnetic shield formed of an electrically conductive and magnetically shielding material, the first and the second magnetic shields disposed to define a read gap therebetween;

a spin valve structure disposed between the first and second magnetic shields, the spin valve structure including a dual spin valve arrangement, the dual spin valve arrangement having a top and bottom spin self pinned layer and a free ferromagnetic layers disposed therebetween; and

a biasing layer disposed adjacent only the top self pinned layer in a passive region for pinning the top self-pinned layer.

16. The magnetic storage system of claim 15 , wherein the CPP GMR sensor further comprises:

a hard bias layer separate and distinct from the biasing layer formed proximate the bottom self-pinned layer in a passive region for biasing the bottom self pinned layer;

a first metal oxide layer disposed between the biasing layer and the hard bias layer for providing an insulation layer to the hard bias layer; and

a second metal oxide layer formed above the biasing layer.

17. The magnetic storage system of claim 16 , wherein the metal oxide layers further comprises NiO.

18. The magnetic storage system of claim 16 , wherein the CPP GMR sensor further comprises a ferromagnetic layer disposed over the second metal oxide layer and the self-pinned layer, wherein the second metal oxide layer removes exchange coupling to the hard bias layer.

19. The magnetic storage system of claim 18 , wherein the CPP GMR sensor further comprises a Ta layer formed between the ferromagnetic layer and the second shield.

20. The magnetic storage system of claim 19 , wherein the ferromagnetic layer comprises NiFe.

21. The magnetic storage system of claim 15 , wherein the CPP GMR sensor further comprises a first and second metal oxide layer formed under and above the biasing layer.

22. The magnetic storage system of claim 21 , wherein the metal oxide layers further comprises NiO.

23. The magnetic storage system of claim 22 , wherein the CPP GMR sensor further comprises further comprises a ferromagnetic layer disposed below the second shield and over the second metal oxide layer and the self-pinned layer, wherein the second metal oxide layer removes exchange coupling to the hard bias layer.

24. The magnetic storage system of claim 23 , wherein the CPP GMR sensor further comprises a Ta layer formed between the ferromagnetic layer and the second shield.

25. The magnetic storage system of claim 23 , wherein the ferromagnetic layer comprises NiFe.

26. The magnetic storage system of claim 15 , wherein the first and second shields function as electrodes for supplying current to the spin valve structure.

27. The magnetic storage system of claim 15 , wherein the biasing layer comprises a layer of alpha-Fe 2 O 3 , the layer of alpha-Fe 2 O 3 pinning the top self-pinned layer.

28. The magnetic storage system of claim 27 , wherein the layer of alpha-Fe 2 O 3 pins the top portion of the top self-pinned layer by providing higher coercivity (H C ) to the top self-pinned layer.

29. A method for providing a dual current-perpendicular-to-plane (CPP) GMR sensor with improved top pinning, comprising:

forming a first magnetic shield of an electrically conductive and magnetically shielding material;

forming a second magnetic shield of an electrically conductive and magnetically shielding material, the first and the second magnetic shields disposed to define a read gap therebetween;

forming a spin valve structure between the first and second magnetic shields, the spin valve structure including a dual spin valve arrangement, the dual spin valve arrangement having a top and bottom spin self-pinned layer and a free ferromagnetic layers disposed therebetween; and

forming a biasing layer disposed adjacent only the top self-pinned layer in a passive region for pinning the top self-pinned layer.

30. The method of claim 29 further comprising:

forming a hard bias layer separate and distinct from the biasing layer formed proximate the bottom self-pinned layer in a passive region for biasing the bottom self pinned layer;

forming a first metal oxide layer between the biasing layer and the hard bias layer for providing an insulation layer to the hard bias layer; and

forming a second metal oxide layer above the biasing layer.

31. The method of claim 30 further comprises forming a ferromagnetic layer over the second metal oxide layer and the self-pinned layer, wherein the second metal oxide layer removes exchange coupling to the hard bias layer.

32. The method of claim 31 further comprising forming a Ta layer between the ferromagnetic layer and the second shield.