Method and apparatus for providing a magnetic read sensor having a thin pinning layer and improved magnetoreistive coefficient
View Patent ↗A method and apparatus for providing a magnetic read sensor having a thin pinning layer and improved magnetoresistive coefficient ΔR/R is disclosed. A thin IrMn alloy pinning layer is disposed adjacent a composite pinned layer, wherein the percentage of iron in the pinned layer adjacent the thin IrMn alloy pinning layer in the range of 20-40% to provide maximum pinning.
1. A magnetic read head, comprising:
a ferromagnetic pinned layer structure comprising at least two pinned layers, the ferromagnetic pinned structure having a high positive magnetostriction;
an iridium manganese (IrMn) alloy pinning layer, exchange coupled to the pinned layer structure, for pinning the magnetic moment of the pinned layer structure;
a free layer structure having a first magnetization that is free to rotate; and
a spacer layer disposed between the free layer structure and the ferromagnetic pinned layer structure;
wherein the at least two pinned layers of the ferromagnetic pinned layer structure provide maximum exchange coupling between the pinned layer structure and the iridium manganese alloy pinning layer and wherein thickness of at least two of the pinned layers are equal.
2. The magnetic read head of claim 1 , wherein the spacer layer is a manganese oxide layer.
3. The magnetic read head of claim 1 , wherein the pinned layer comprises a cobalt iron layer, an interlayer and a cobalt iron boron layer, wherein the cobalt iron layer is formed on the pinning layer.
4. The magnetic read head of claim 1 , wherein the free layer structure comprises a cobalt iron layer and a cobalt iron boron layer, wherein the cobalt iron layer is formed on the spacer layer.
5. The magnetic read head of claim 4 further comprising a tantalum layer formed on the cobalt iron boron layer and a nickel iron layer formed on the tantalum layer.
6. The magnetic read head of claim 1 , wherein the spacer layer further comprising a copper spacer layer for providing a conductive spacer layer between the free layer and the pinned layer.
7. The magnetic read head of claim 6 , wherein the pinned layer further comprises a third layer, the third layer comprising a Co 2 XY layer, where X is a material chosen from a group that includes manganese, iron and chromium, and Y is a material chosen from a group that includes silicon, germanium and aluminum.
8. The magnetic read head of claim 7 , wherein the free layer structure comprises a synthetic free layer comprising a first and second free layer separated by an interlayer, the first and second free layer having antiparallel magnetic orientations.
9. The magnetic read head of claim 8 , wherein the first free layer comprises a layer comprising a cobalt iron free layer and a Co 2 XY layer formed on the copper spacer layer between the cobalt iron free layer and the copper spacer layer, where X is a material chosen from a group that includes manganese, iron and chromium, and Y is a material chosen from a group that includes silicon, germanium and aluminum.
10. The magnetic read head of claim 8 , wherein the second free layer comprises a cobalt iron free layer formed on the interlayer and a nickel iron layer formed on the cobalt iron free layer.
11. A magnetic storage device, comprising:
a magnetic media for storing data thereon;
a motor, coupled to the magnetic media, for translating the magnetic media;
a transducer for reading and writing data on the magnetic media; and
an actuator, coupled to the transducer, for moving the transducer relative to the magnetic media;
wherein the transducer includes a read sensor comprising:
a ferromagnetic pinned layer structure comprising at least two pinned layers, the ferromagnetic pinned structure having a high positive magnetostriction;
an iridium manganese (IrMn) alloy pinning layer, exchange coupled to the pinned layer structure, for pinning the magnetic moment of the pinned layer structure;
a free layer structure having a first magnetization that is free to rotate; and
a spacer layer disposed between the free layer structure and the ferromagnetic pinned layer structure;
wherein the at least two pinned layers of the ferromagnetic pinned layer structure provide maximum exchange coupling between the pinned layer structure and the iridium manganese alloy pinning layer and wherein thickness of at least two of the pinned layers are equal.
12. The magnetic read head of claim 11 , wherein the spacer layer is a manganese oxide layer.
13. The magnetic read head of claim 11 , wherein the pinned layer comprises a cobalt iron layer, an interlayer and a cobalt iron boron layer, wherein the cobalt iron layer is formed on the pinning layer and wherein the free layer structure comprises a cobalt iron layer and a cobalt iron boron layer, wherein the cobalt iron layer is formed on the spacer layer.
14. The magnetic read head of claim 13 further comprising a tantalum layer formed on the cobalt iron boron layer and a nickel iron layer formed on the tantalum layer.
15. The magnetic read head of claim 11 , wherein the spacer layer further comprising a copper spacer layer for providing a conductive spacer layer between the free layer and the pinned layer.
16. The magnetic read head of claim 15 , wherein the pinned layer further comprises a third layer, the third layer comprising a Co 2 XY layer, where X is a material chosen from a group that includes manganese, iron and chromium, and Y is a material chosen from a group that includes silicon, germanium and aluminum.
17. The magnetic read head of claim 16 , wherein the free layer structure comprises a synthetic free layer comprising a first and second free layer separated by an interlayer, the first and second free layer having antiparallel magnetic orientations.
18. The magnetic read head of claim 17 , wherein the first free layer comprises a layer comprising a cobalt iron free layer and a Co 2 XY layer formed on the copper spacer layer between the cobalt iron free layer and the copper spacer layer, where X is a material chosen from a group that includes manganese, iron and chromium, and Y is a material chosen from a group that includes silicon, germanium and aluminum.
19. The magnetic read head of claim 17 , wherein the second free layer comprises a cobalt iron free layer formed on the interlayer and a nickel iron layer formed on the cobalt iron free layer.
20. A method for providing a magnetic read sensor having a thin pinning layer and improved magnetoresistive coefficient, comprising:
forming a ferromagnetic pinned layer structure comprising at least two pinned layers, the ferromagnetic pinned structure having a high positive magnetostriction;
forming an iridium manganese (IrMn) alloy pinning layer, exchange coupled to the pinned layer structure, for pinning the magnetic moment of the pinned layer structure;
forming a free layer structure having a first magnetization that is free to rotate; and
forming a spacer layer disposed between the free layer structure and the ferromagnetic pinned layer structure;
wherein the at least two pinned layers of the ferromagnetic pinned layer structure provide maximum exchange coupling between the pinned layer structure and the iridium manganese alloy pinning layer and wherein thickness of at least two of the pinned layers are equal.