Magnetic memory cell construction
A magnetic tunnel junction cell having a free layer, a ferromagnetic pinned layer, and a barrier layer therebetween. The free layer has a central ferromagnetic portion and a stabilizing portion radially proximate the central ferromagnetic portion. The construction can be used for both in-plane magnetic memory cells where the magnetization orientation of the magnetic layer is in the stack film plane and out-of-plane magnetic memory cells where the magnetization orientation of the magnetic layer is out of the stack film plane, e.g., perpendicular to the stack plane.
1. A magnetic tunnel junction cell comprising:
a ferromagnetic free layer, wherein the ferromagnetic free layer comprises a central ferromagnetic portion and a stabilizing portion, the stabilizing portion positioned radially proximate the central ferromagnetic portion, the stabilizing portion comprising an antiferromagnetic material, and wherein the central ferromagnetic portion and the stabilizing portion meet;
a ferromagnetic pinned layer; and
a barrier layer,
wherein the barrier layer is positioned between the ferromagnetic free layer and ferromagnetic pinned layer.
2. The magnetic tunnel junction cell of claim 1 wherein the stabilizing portion stabilizes the central ferromagnetic portion by exchange coupling.
3. The magnetic tunnel junction cell of claim 1 , wherein stabilizing portion comprises PtMn, FeMn, IrMn, or CrMnPt.
4. The magnetic tunnel junction cell of claim 1 further comprising an antiferromagnetic pinning layer proximate the ferromagnetic pinned layer.
5. The magnetic tunnel junction cell of claim 4 , wherein the ferromagnetic pinned layer is a synthetic antiferromagnetic trilayer.
6. The magnetic tunnel junction cell of claim 5 , wherein the antiferromagnetic pinning layer comprises PtMn or IrMn.
7. The magnetic tunnel junction cell of claim 1 wherein the stabilizing portion has a radial thickness of about 2 to 6 nm.
8. The magnetic tunnel junction cell of claim 1 further comprising an electrode that is in electrical contact with the ferromagnetic free layer.
9. The magnetic tunnel junction cell of claim 8 wherein the central ferromagnetic portion has a first diameter and the electrode has a second diameter and the second diameter is smaller than the first diameter.
10. The magnetic tunnel junction cell of claim 1 wherein the central ferromagnetic portion has an out-of-plane magnetization orientation and the pinned layer has an out-of-plane magnetization orientation.
11. The magnetic tunnel junction cell of claim 1 wherein the central ferromagnetic portion has an in-plane magnetization orientation and the pinned layer has an in-plane magnetization orientation.
12. A magnetic tunnel junction cell comprising:
a ferromagnetic free layer, wherein the ferromagnetic free layer comprises a central ferromagnetic portion and a stabilizing portion, the stabilizing portion positioned radially proximate the central ferromagnetic portion, the stabilizing portion comprising an antiferromagnetic material, and the central ferromagnetic portion having a first diameter;
a ferromagnetic pinned layer;
a barrier layer; and
an electrode that is in electrical contact with the ferromagnetic free layer, the electrode having a second diameter,
wherein the barrier layer is positioned between the ferromagnetic free layer and ferromagnetic pinned layer, and the second diameter is smaller than the first diameter.
13. The magnetic tunnel junction cell according to claim 12 , wherein the stabilizing portion stabilizes the central ferromagnetic portion by exchange coupling.
14. The magnetic tunnel junction cell of claim 12 , wherein stabilizing portion comprises PtMn, FeMn, IrMn, or CrMnPt.
15. The magnetic tunnel junction cell of claim 12 further comprising an antiferromagnetic pinning layer proximate the ferromagnetic pinned layer.
16. The magnetic tunnel junction cell of claim 15 , wherein the ferromagnetic pinned layer is a synthetic antiferromagnetic trilayer.
17. The magnetic tunnel junction cell of claim 16 , wherein the antiferromagnetic pinning layer comprises PtMn or IrMn.
18. The magnetic tunnel junction cell of claim 12 , wherein the stabilizing portion has a radial thickness of about 2 to 6 nm.
19. The magnetic tunnel junction cell of claim 12 , wherein the central ferromagnetic portion has an out-of-plane magnetization orientation and the pinned layer has an out-of-plane magnetization orientation.
20. The magnetic tunnel junction cell of claim 12 , wherein the central ferromagnetic portion has an in-plane magnetization orientation and the pinned layer has an in-plane magnetization orientation.