Magnetoresistive sensor with tunnel barrier and method

1. A device comprising:

a magnetoresistive sensor comprising a magnetic tunnel junction, the magnetic tunnel junction including a barrier layer, the barrier layer including carbon,

wherein the magnetic tunnel junction has a magnetoresistance ratio greater than 75%.

2. The device of claim 1 , wherein the barrier layer comprises pyrolytic carbon.

3. The device of claim 1 , wherein the barrier layer comprises graphene.

4. The device of claim 1 , wherein the barrier layer comprises graphite.

5. The device of claim 1 , wherein the barrier layer is disposed between a first ferromagnetic layer and a second ferromagnetic layer.

6. The device of claim 5 , wherein the first ferromagnetic layer has a fixed magnetization orientation.

7. The device of claim 5 , comprising:

a first antiferromagnetic layer disposed proximate to the first ferromagnetic layer, the first antiferromagnetic layer being configured to pin the orientation of the first ferromagnetic layer.

8. The device of claim 7 , comprising:

a second antiferromagnetic layer disposed proximate to the second ferromagnetic layer, the second antiferromagnetic layer being configured to pin the orientation of the second ferromagnetic layer.

9. The device of claim 8 , wherein the first ferromagnetic layer comprises a third ferromagnetic layer disposed proximate to the first antiferromagnetic layer, a non-magnetic layer disposed proximate to the third ferromagnetic layer and a fourth ferromagnetic layer disposed proximate to the non-magnetic layer.

10. The device of claim 1 , wherein the magnetoresistive sensor is a read head configured to be used in magnetic data storage systems to detect magnetically encoded information stored on a magnetic data storage medium.

11. The device of claim 1 , wherein the magnetoresistive sensor is configured to be used in a global positioning system.

12. The device of claim 1 , wherein the magnetoresistive sensor is a field sensor configured to act as a position sensor for linear or angular positions.

13. A method of manufacturing a magnetoresistive sensor comprising:

forming a magnetic tunnel junction having a magnetoresistance ratio greater than 75%;

forming a barrier layer, the barrier layer including carbon; and

forming an additional layer.

14. The method of claim 13 , wherein the barrier layer includes pyrolytic carbon.

15. The method of claim 13 , wherein the barrier layer includes graphene.

16. The method of claim 13 , wherein the barrier layer includes graphite.

17. The method of claim 13 , comprising:

forming a first ferromagnetic layer, wherein the barrier layer is formed proximate to the first ferromagnetic layer.

18. The method of claim 17 , wherein forming the first ferromagnetic layer comprises:

forming a third ferromagnetic layer disposed proximate to a first antiferromagnetic layer;

forming a non-magnetic layer proximate to the third ferromagnetic layer; and

forming a fourth ferromagnetic layer proximate to the non-magnetic layer.

19. The method of claim 17 , comprising:

forming a second ferromagnetic layer proximate to the barrier layer.

20. The method of claim 19 , comprising forming the first ferromagnetic layer proximate to a first antiferromagnetic layer.

21. The method of claim 20 , comprising forming a second antiferromagnetic layer proximate to the second ferromagnetic layer.

22. An integrated circuit comprising:

a magnetoresistive sensor comprising a magnetic tunnel junction including a barrier layer, the barrier layer including carbon; and

one or more additional layers,

wherein the magnetic tunnel junction has a magnetoresistance ratio greater than 75%.