Spin valve sensor having one of two AP pinned layers made of cobalt
View Patent ↗In one illustrative example of the invention, a spin valve sensor includes a free layer structure; an antiparallel (AP) pinned layer structure; and a non-magnetic electrically conductive spacer layer in between the free layer structure and the AP pinned layer structure. The AP pinned layer structure includes a first AP pinned layer; a second AP pinned layer; and an antiparallel coupling (APC) layer formed between the first and the second AP pinned layer. One of the first and the second AP pinned layers consists of cobalt and the other one includes cobalt-iron. The pure cobalt may be provided in the first AP pinned layer or the second AP pinned layer. Advantageously, the use of cobalt in one of the AP pinned layers increases the Δr/R of the spin valve sensor.
1. A spin valve sensor for a magnetic head, comprising;
a free layer structure having a cobalt-iron layer;
an antiparallel (AP) pinned layer structure;
a non-magnetic electrically conductive spacer layer in between the free layer structure and the AP pinned layer structure;
the AP pinned layer structure including;
a first AP pinned layer;
a second AP pinned layer;
an antiparallel coupling (APC) layer formed between the first and the second AP pinned layers;
one of the first and the second AP pinned layers consisting of cobalt and including no iron content;
the other of the first and the second AP pinned layers comprising a cobalt-iron layer; and
an antiferromagnetic (AFM) pinning layer for pinning the first AP pinned layer.
2. The spin valve sensor of claim 1 , wherein a coercivity Hc of the spin valve sensor is less than 5 Oersteds.
3. The spin valve sensor of claim 1 , wherein a Δr/R of the spin valve sensor is greater than 12%.
4. The spin valve sensor of claim 1 , wherein the one AP pinned layer is the first AP pinned layer.
5. The spin valve sensor of claim 1 , wherein the one AP pinned layer is the second AP pinned layer.
6. The spin valve-sensor of claim 1 , wherein the free layer structure further comprises a nickel-iron layer.
7. The spin valve sensor of claim 1 , wherein the AFM pinning layer comprises platinum-manganese (PtMn).
8. The spin valve sensor of claim 1 , which is a bottom-pinned spin valve sensor wherein the AFM pinning layer is formed below the AP pinned layer structure.
9. A disk drive, comprising:
a housing;
a magnetic disk rotatably supported in that housing;
a magnetic head assembly;
a support mounted in the housing for supporting the magnetic head assembly so as to be in a transducing relationship with the magnetic disk;
a processor connected to the magnetic head assembly, to the spindle motor, and to the actuator for exchanging signals with the magnetic head assembly for controlling movement of the magnetic disk and for controlling the position of the magnetic head assembly;
the magnetic head assembly including a read head;
the read head including a spin valve sensor;
the spin valve sensor comprising:
a free layer structure having a cobalt-iron layer;
an antiparallel (AP) pinned layer structure;
a non-magnetic electrically conductive spacer layer in between the free layer structure and the AP pinned layer structure;
the AP pinned layer structure including:
a first AP pinned layer;
a second AP pinned layer;
an antiparallel coupling (APC) layer formed between the first and the second AP pinned layer;
one of the first and the second AP pinned layers consisting of cobalt and including no iron content;
the other of the first and the second AP pinned layers comprising a cobalt-iron layer; and
an antiferromagnetic (AFM) pinning layer for pinning the first AP pinned layer.
10. The disk drive of claim 9 , wherein the one AP pinned layer is the first AP pinned layer.
11. The disk drive of claim 9 , wherein the one AP pinned layer is the second AP pinned layer.
12. The disk drive of claim 9 , wherein the free layer structure further comprises a nickel-iron layer.
13. The disk drive of claim 9 , wherein the AFM pinning layer comprises platinum-manganese (PtMn).
14. The disk drive of claim 9 , which is a bottom-pinned spin valve sensor wherein the AFM pinning layer is formed below the AP pinned layer structure.
15. The disk drive of claim 9 , wherein a coercivity H c of the spin valve sensor is less that 5 Oersteds.
16. The disk drive of claim 9 , wherein a Δr/R of the spin valve sensor is greater than 12%.
17. A method of making a spin valve sensor for a magnetic head, comprising:
forming an antiparallel (AP) pinned layer structure and a free layer structure which are separated by a non-magnetic electrically conductive spacer layer;
forming the AP pinned layer structure with a first AP pinned layer, a second AP pinned layer, an antiparallel coupling (APC) layer;
forming an antiferromagnetic (AFM) pinning layer for pinning the first AP pinned layer;
wherein the free layer structure has a cobalt-iron layer;
wherein one of the first and the second AP pinned layers consists of cobalt and includes no iron content; and
wherein the other of the first and the second AP pinned layers comprises a cobalt-iron layer.
18. The method of claim 17 , wherein the one AP pinned layer is the first AP pinned layer.
19. The method of claim 17 , wherein the one AP pinned layer is the second AP pinned layer.
20. The method of claim 17 , wherein the AFM pinning layer is formed below the AP pinned layer structure.
21. The method of claim 17 , wherein the AFM pinning layer is formed above the AP pinned layer structure.