Magnetoresistive sensor having seed layer hysteresis suppression
Methods and apparatus for a magnetoresistive (MR) sensor including a seed layer having a CoFe layer for canceling hysteresis in the MR sensor. The MR stackup can include a free layer and a reference layer. The seed layer having CoFe provides a desired texturing of the stackup to cancel hysteresis effects.
1. A magnetoresistive sensor, comprising
a free layer;
an insulative barrier layer;
a reference layer, wherein the free layer and the reference layer are on opposite sides of the barrier layer; and
a seed layer comprising non-adjacent first and second layers of CoFe configured to interface with the reference layer for canceling hysteresis in the magnetoresistive sensor.
2. The sensor according to claim 1 , wherein the seed layer comprises at least one layer of Cu and at least one layer of Ta.
3. The sensor according to claim 1 , wherein the seed layer comprises alternating layers of Cu and Ta.
4. The sensor according to claim 1 , wherein the first layer of CoFe is about 5 nm thick.
5. The sensor according to claim 1 , wherein the first layer of CoFe is between about 4 nm and 6 nm thick.
6. The sensor according to claim 1 , further including a bias layer adjacent the free layer to provide a double pinning configuration.
7. The sensor according to claim 1 , wherein the seed layer further comprises a layer of Ru abutting the first layer of CoFe.
8. The sensor according to claim 7 , wherein the Ru layer interfaces with the reference layer.
9. The sensor according to claim 7 , wherein the seed layer further comprises a layer of NiFe.
10. A method, comprising:
forming a free layer and a reference layer on opposite sides of an insulative barrier layer; and
interfacing the reference layer with a seed layer comprising non-adjacent first and second layers of CoFe for canceling hysteresis in a magnetoresistive sensor.
11. The method according to claim 10 , wherein the seed layer comprises at least one layer of Cu and at least one layer of Ta.
12. The method according to claim 10 , wherein the seed layer comprises alternating layers of Cu and Ta.
13. The method according to claim 10 , wherein the first layer of CoFe is about 5 nm thick.
14. The method according to claim 10 , wherein the first layer of CoFe is between about 4 nm and 6 nm thick.
15. The method according to claim 10 , further including providing a bias layer adjacent the free layer to provide a double pinning configuration.
16. The method according to claim 10 , wherein the seed layer further comprises a layer of Ru abutting the first layer of CoFe.
17. The method according to claim 16 , wherein the Ru layer interfaces with the reference layer.
18. The method according to claim 16 , wherein the seed layer further comprises a layer of NiFe.
19. A magnetoresistive sensor, comprising
a free layer;
an insulative barrier layer;
a reference layer, wherein the free layer and the reference layer are on opposite sides of the barrier layer; and
a seed layer means for canceling hysteresis in the magnetoresistive sensor, wherein the seed layer means interfaces with the reference layer,
wherein the seed layer means comprises non-adjacent first and second layers of CoFe.
20. The sensor according to claim 19 , wherein the seed layer means further comprises a layer of Ru abutting the first layer of CoFe.
21. The sensor according to claim 19 , wherein the first layer of CoFe is between about 4 nm and about 6 nm in thickness.
22. The sensor according to claim 19 , wherein the seed layer means comprises at least one layer of Cu and at least one layer of Ta.
23. The sensor according to claim 22 , wherein the first layer of CoFe is about 5 nm thick.