Magnetic memory cell having a soft reference layer

1. A magnetic memory cell, comprising:

a data layer;

a soft reference layer having a lower magnetic energy than said data layer; and

a spacer layer between said data layer and said reference layer.

2. The magnetic memory cell of claim 1 , wherein said soft reference layer has a smaller anisotropy than said data layer.

3. The magnetic memory cell of claim 2 , wherein said smaller anisotropy includes a smaller shape anisotropy.

4. The magnetic memory cell of claim 1 , wherein a ratio of magnetic energy to thermal energy of said soft reference layer is less than 50.

5. The magnetic memory cell of claim 1 , wherein said soft reference layer is superparamagnetic.

6. The magnetic memory cell of claim 1 , wherein said soft reference layer substantially forms a shape having a low aspect ratio.

7. The magnetic memory cell of claim 1 , wherein said soft reference layer substantially forms a circle.

8. The magnetic memory cell of claim 1 , wherein said soft reference layer comprises a plurality of dots, each of which is smaller than said data layer.

9. The magnetic memory cell of claim 1 , wherein said soft reference layer has a smaller volume than said data layer.

10. The magnetic memory cell of claim 1 , wherein said soft reference layer has a smaller planar area than said data layer.

11. The magnetic memory cell of claim 1 , wherein said soft reference layer is thinner than said data layer.

12. The magnetic memory cell of claim 1 , wherein said soft reference layer is laterally narrower than said data layer.

13. The magnetic memory cell of claim 1 , wherein said soft reference layer is more thermally unstable than said data layer.

14. The magnetic memory cell of claim 1 , wherein said data layer comprises more than one layer of materials.

15. The magnetic memory cell of claim 1 , wherein said data layer is proximate a ferromagnetic material that is configured to act as a flux guide for magnetic fields emanating from said data layer.

16. The magnetic memory cell of claim 15 , wherein said ferromagnetic material is a cladding around a conductor.

17. A method for making magnetic memory cell having a soft reference layer, comprising:

forming a data layer;

forming a soft reference layer having a lower magnetic energy than said data layer; and

forming a spacer layer between said data layer and said soft reference layer.

18. The method of claim 17 , wherein said forming a soft reference layer comprises forming a layer having a smaller anisotropy than said data layer.

19. The method of claim 18 , wherein said smaller anisotropy includes a smaller shape anisotropy.

20. The method of claim 19 , wherein said forming a soft reference layer comprises patterning said soft reference layer to substantially form a shape having a low aspect ratio.

21. The method of claim 19 , wherein said forming a soft reference layer comprises patterning said soft reference layer to substantially form a circle.

22. The method of claim 19 , wherein said forming a soft reference layer comprises forming a plurality of dots, each of which is smaller than said data layer.

23. The method of claim 17 , wherein said forming a soft reference layer comprises forming a soft reference layer having a smaller volume than said data layer.

24. The method of claim 17 , wherein said forming a soft reference layer comprises forming a soft reference layer having a smaller planar area than said data layer.

25. The method of claim 17 , wherein said forming a soft reference layer comprises forming a laterally narrower soft reference layer than said data layer.

26. The method of claim 17 , wherein said forming a data layer comprises forming more than one layer of materials.

27. The method of claim 17 , wherein said forming a data layer comprises forming a data layer near a ferromagnetic material that is configured to act as a flux guide for magnetic fields emanating from said data layer.

28. The magnetic memory cell of claim 27 , wherein said ferromagnetic material is a cladding around a conductor.

29. A nonvolatile memory array comprising a plurality of magnetic memory cells, each of said magnetic memory cells being made by a process comprising:

forming a data layer;

forming a soft reference layer having a lower magnetic energy than said data layer; and

forming a spacer layer between said data layer and said soft reference layer.