Magnetic element with a fast spin transfer torque writing procedure
View Patent ↗A magnetic tunnel junction, including a reference layer having a fixed magnetization direction, a first storage layer having a magnetization direction that is adjustable relative to the magnetization direction of the reference layer by passing a write current through said magnetic tunnel junction, and an insulating layer disposed between said reference layer and first storage layer; characterized in that the magnetic tunnel junction further comprises a polarizing device to polarize the spins of the write current oriented perpendicular with the magnetization direction of the reference layer; and wherein said first storage layer has a damping constant above 0.02. A magnetic memory device formed by assembling an array of the magnetic tunnel junction can be fabricated resulting in lower power consumption.
1. A magnetic tunnel junction, comprising:
a reference layer having a fixed magnetization direction,
a first storage layer having a magnetization direction that is adjustable relative to the magnetization direction of the reference layer by passing a write current through said magnetic tunnel junction, and
an insulating layer disposed between said reference layer and first storage layer;
wherein
the magnetic tunnel junction further comprises a polarizing device ( 25 ) to polarize the spins of the write current oriented perpendicular with the magnetization direction of the reference layer;
and wherein
said first storage layer has a damping constant above 0.02.
2. The magnetic tunnel junction of claim 1 , wherein the polarizing device is a polarizing layer having a magnetization oriented perpendicular to the magnetization direction of the first storage layer.
3. The magnetic tunnel junction of claim 1 , wherein the magnetization of said polarizing layer is oriented out of plane and the respective magnetizations of the reference and first storage layers are oriented in-plane.
4. The magnetic tunnel junction of claim 1 , wherein the magnetization of said polarizing layer is oriented in-plane and the respective magnetizations of the reference and first storage layers are oriented out-of-plane.
5. The magnetic tunnel junction of claim 1 , wherein the magnetization of said polarizing layer and the respective magnetizations of the reference and first storage layers are oriented in-plane but perpendicular one to another.
6. The magnetic tunnel junction of claim 1 , wherein said first storage layer is made from a transition metal-based alloy containing at least one element chosen from Pt, Pd, Ir, Au, or a rare earth element.
7. The magnetic tunnel junction of claim 6 , wherein the transition metal-based alloy is a Co, Fe, or Ni-based alloy.
8. The magnetic tunnel junction of claim 6 , wherein said at least one rare earth element is chosen from Sm, Tb, Gd, Er, or Ho.
9. The magnetic tunnel junction of claim 1 , wherein said magnetic tunnel junction further comprises a second storage layer allowing a magnetoresistance greater than 50%.
10. The magnetic tunnel junction of claim 9 , wherein said second storage layer contacts the insulating layer.
11. The magnetic tunnel junction of claim 9 , wherein said second storage layer is made from a transition metal-based alloy.
12. The magnetic tunnel junction of claim 11 , wherein the transition metal-based alloy is a Co, Fe, or Ni-based alloy.
13. The magnetic tunnel junction of claim 9 , wherein said magnetic tunnel junction further comprises a coupling layer disposed between the first storage layer and the second storage layer.
14. The magnetic tunnel junction of claim 13 , wherein said coupling layer is an antiferromagnetically coupling layer coupling antiferromagnetically said first and second storage layers.
15. The magnetic tunnel junction of claim 14 , wherein said antiferromagnetically coupling layer is made of ruthenium.
16. The magnetic tunnel junction of claim 14 , wherein said antiferromagnetically coupling layer has a thickness comprised between 0.6 nm and 0.9 nm.
17. The magnetic tunnel junction of claim 13 , wherein said coupling layer is an antiferromagnetic layer.
18. The magnetic tunnel junction of claim 17 , wherein said antiferromagnetic layer is made of an alloy chosen from IrMn or PtMn.
19. The magnetic tunnel junction of claim 17 , wherein said antiferromagnetic layer has a thickness comprised between 0.5 nm and 3 nm.
20. A magnetic element comprising:
a magnetic tunnel junction formed from an insulating layer disposed between a reference layer, having a fixed magnetization direction, and a first storage layer having a magnetization direction that is adjustable relative to the magnetization direction of the reference layer;
a selection transistor being electrically connected to said magnetic tunnel junction and controllable via a word line; and
a current line, electrically connected to said magnetic tunnel junction, said current line passing a write current for switching the second magnetization of said first storage layer;
wherein
said magnetic tunnel junction further comprises a polarizing device to polarize the spins of the write current oriented perpendicular with the magnetization direction of the reference layer during a write operation;
and wherein
said first storage layer has a damping constant above 0.02.
21. The magnetic element of claim 20 , wherein the polarizing device is a polarizing layer having a magnetization oriented perpendicular to the magnetization direction of the first storage layer.
22. The magnetic element of claim 20 , wherein the magnetization of said polarizing layer is oriented out of plane and the respective magnetizations of the reference and first storage layers are oriented in-plane.
23. The magnetic element of claim 20 , wherein the magnetization of said polarizing layer is oriented in-plane and the respective magnetizations of the reference and first storage layers are oriented out-of-plane.
24. The magnetic element of claim 20 , wherein the magnetization of said polarizing layer and the respective magnetizations of the reference and first storage layers are oriented in-plane and perpendicular one to another.
25. The magnetic element of claim 20 , wherein said first storage layer is made from a transition metal-based alloy containing at least one element chosen from Pt, Pd, Ir, Au, or a rare earth element.
26. The magnetic element of claim 25 , wherein the transition metal-based alloy is a Co, Fe, or Ni-based alloy.
27. The magnetic element of claim 25 , wherein said at least one rare earth element is chosen from Sm, Tb, Gd, Er, or Ho.
28. The magnetic element of claim 20 , wherein said magnetic tunnel junction further comprises a second storage layer having a magnetoresistance greater than 50%.
29. The magnetic element of claim 28 , wherein said second storage layer contacts the insulating layer.
30. The magnetic element of claim 28 , wherein said second storage layer is made from a transition metal-based alloy.
31. The magnetic element of claim 30 , wherein the transition metal-based alloy is a Co, Fe, or Ni-based alloy.
32. The magnetic element of claim 28 , wherein said magnetic tunnel junction further comprises a coupling layer disposed between the first storage layer and the second storage layer.
33. The magnetic element of claim 32 , wherein said coupling layer is an antiferromagnetically coupling layer coupling antiferromagnetically said first and second storage layers.
34. The magnetic element of claim 33 , wherein said antiferromagnetically coupling layer is made of ruthenium.
35. The magnetic element of claim 33 , wherein said antiferromagnetically coupling layer has a thickness comprised between 0.6 nm and 0.9 nm.
36. The magnetic element of claim 32 , wherein said coupling layer is an antiferromagnetic layer.
37. The magnetic element of claim 36 , wherein said antiferromagnetic layer is made of an alloy chosen from IrMn or PtMn.
38. The magnetic element of claim 36 , wherein said antiferromagnetic layer has a thickness comprised between 0.5 nm and 2 nm.
39. A magnetic memory device formed by assembling an array comprising a plurality of magnetic element, each magnetic element comprising:
a magnetic tunnel junction formed from a reference layer having a fixed magnetization direction, a first storage layer having a magnetization direction that is adjustable relative to the magnetization direction of the reference layer and having a damping constant above 0.02, an insulating layer disposed between said reference layer and first storage layer, and a polarizing device to polarize the spins of the write current oriented perpendicular with the magnetization direction of the reference layer; and
a current line, electrically connected to said magnetic tunnel junction, said current line passing a write current for switching the second magnetization of said first storage layer;
wherein
several magnetic tunnel junctions of said magnetic elements can be addressed simultaneously by the current line and the word line.
40. The magnetic memory device of claim 39 , wherein said each magnetic element further comprises a selection transistor and a word line, the selection transistor being electrically connected to said magnetic tunnel junction and controllable via the word line.