Method for improving hard bias properties of layers in a magnetoresistive sensor

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

forming a ferromagnetic free layer structure that has a magnetic moment;

forming a ferromagnetic pinned layer structure having a magnetic moment;

forming a nonmagnetic conductive spacer layer between the free layer structure and the pinned layer structure;

forming an anti-ferromagnetic pinning layer coupled to the pinned layer structure for pinning the magnetic moment of the pinned layer structure;

forming hard magnetic thin films on both sides of at least a portion of the free layer structure, the ferromagnetic pinned layer structure, the nonmagnetic conductive spacer layer and the anti-ferromagnetic pinning layer; and

forming a hard bias seedlayer structure adjacent to and on opposite sides of at least a portion of the free layer structure, the ferromagnetic pinned layer structure, the nonmagnetic conductive spacer layer and the anti-ferromagnetic pinning layer, wherein the forming the hard bias seedlayer structure comprises forming at least a first layer comprising silicon and a second layer comprising chromium or chromium molybdenum.

2. The method of claim 1 , wherein the forming the anti-ferromagnetic pinning layer further comprising forming a layer of platinum manganese.

3. The method of claim 1 , wherein the forming the hard bias seedlayer structure further comprises forming a layer of tantalum adjacent the silicon layer.

4. The method of claim 3 , wherein the forming a layer of tantalum adjacent the silicon layer further comprises forming the tantalum and silicon layer with equal thickness.

5. The method of claim 3 , wherein the forming a layer of tantalum adjacent the silicon layer further comprises forming the tantalum layer with a thickness half a thickness of the silicon layer.

6. The method of claim 3 , wherein the forming a layer of tantalum further comprises forming a tantalum-chromium alloy layer.

7. The method of claim 6 , wherein the forming the tantalum-chromium alloy layer further comprises forming the tantalum-chromium alloy layer silicon layer with equal thickness.

8. The method of claim 6 , wherein the forming the tantalum-chromium alloy layer further comprises forming the tantalum-chromium alloy layer thickness half a thickness of the silicon layer.

9. The method of claim 1 , wherein the forming the hard bias seedlayer structure further comprises forming at opposite sides of at least a portion of the free layer structure, the ferromagnetic pinned layer structure, the nonmagnetic conductive spacer layer and the anti-ferromagnetic pinning layer, a first layer of tantalum, a second layer of silicon and a third layer comprising chromium.

10. The method of claim 1 , wherein the forming the hard bias seedlayer structure further comprises forming at opposite sides of at least a portion of the free layer structure, the ferromagnetic pinned layer structure, the nonmagnetic conductive spacer layer and the anti-ferromagnetic pinning layer, a first layer of tantalum, a second layer of silicon and a third layer comprising chromium-molybdenum.

11. The method of claim 10 , wherein the pinning layer comprises platinum manganese.

12. The method of claim 10 , wherein the forming the hard bias seedlayer structure further comprises forming a layer of tantalum adjacent the silicon layer.

13. The method of claim 12 , wherein the forming a layer of tantalum adjacent the silicon layer further comprises forming the tantalum and silicon layer with equal thickness.

14. The method of claim 12 , wherein the forming a layer of tantalum adjacent the silicon layer further comprises forming the tantalum layer with a thickness half a thickness of the silicon layer.

15. The method of claim 12 , wherein the forming a layer of tantalum further comprises forming a tantalum-chromium alloy layer.

16. The method of claim 15 , wherein the forming the tantalum chromium alloy layer further comprises forming the tantalum-chromium alloy layer and the silicon layer with equal thickness.

17. The method of claim 15 , wherein the forming the tantalum-chromium alloy layer further comprises forming the tantalum-chromium alloy lay thickness half a thickness of the silicon layer.

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

forming a spin valve structure including a ferromagnetic free layer, a ferromagnetic

pinned layer and an anti-ferromagnetic pinning layer;

forming hard magnetic thin films adjacent at least a portion of the spin valve structure on both sides of the spin valve structure; and

forming a hard bias seedlayer structure adjacent to and on opposite sides of at least a portion of the spin valve structure, wherein the forming the hard bias seedlayer structure comprises forming at least a first layer comprising silicon and a second layer comprising chromium or chromium molybdenum.

19. The method of claim 18 , wherein the forming the hard bias seedlayer structure further comprises forming at opposite sides of at least a portion of the free layer structure, the ferromagnetic pinned layer structure, the nonmagnetic conductive spacer layer and the anti-ferromagnetic pinning layer, a first layer of tantalum, a second layer of silicon and a third layer comprising chromium.

20. The method of claim 18 , wherein the forming the hard bias seedlayer structure further comprises forming at opposite sides of at least a portion of the free layer structure, the ferromagnetic pinned layer structure, the nonmagnetic conductive spacer layer and the anti-ferromagnetic pinning layer, a first layer of tantalum, a second layer of silicon and a third layer comprising chromium-molybdenum.

21. A method of forming a hard bias seedlayer structure, comprising:

forming a first layer comprising silicon adjacent to and on opposite sides of a spin valve structure; and

forming a second layer comprising chromium or chromium molybdenum adjacent to the first layer.

22. The method of claim 21 further comprising forming a layer of tantalum adjacent the silicon layer.