Perpendicular magnetic tunnel junction device with offset precessional spin current layer

1. A magnetic device, comprising:

a first synthetic antiferromagnetic structure in a first plane having a magnetization vector that is perpendicular to the first plane and having a fixed magnetization direction;

an antiferromagnetic coupling layer in a second plane and disposed above the first synthetic antiferromagnetic structure;

a second synthetic antiferromagnetic structure in a third plane and disposed over the antiferromagnetic coupling layer;

a magnetic reference layer in a fourth plane and disposed over the second synthetic antiferromagnetic structure, the magnetic reference layer having a magnetization vector that is perpendicular to the fourth plane and having a fixed magnetization direction;

a non-magnetic tunnel barrier layer in a fifth plane and disposed over the magnetic reference layer;

a free magnetic layer having a first diameter and disposed in a sixth plane over the non-magnetic tunnel barrier layer, the free magnetic layer having a magnetization vector that is perpendicular to the sixth plane and having a magnetization direction that can switch between a first magnetization direction to a second magnetization direction, the magnetic reference layer, the non-magnetic tunnel barrier layer and the free magnetic layer forming a magnetic tunnel junction; and

a precessional spin current magnetic layer having a second diameter that is less than the first diameter and a center that is offset relative to a center of the free magnetic layer, the precessional spin current magnetic layer disposed in a seventh plane that is physically separated from the free magnetic layer and coupled to the free magnetic layer by a filter coupling layer that may induce ferromagnetic or antiferromagnetic coupling between the free magnetic layer and the filter layer.

2. The magnetic device of claim 1 , wherein the second diameter is in the range of 5 nm to 100 nm.

3. The magnetic device of claim 1 , wherein a ratio of the second diameter to the first diameter is in the range of 0.2 to 0.9.

4. The magnetic device of claim 1 , wherein the precessional spin current magnetic layer is formed from Co x Fe y B z , where y is in the range 40% to 70%, z is in the range 18% to 21%, and x+y+z=100%.

5. The magnetic device of claim 1 , wherein the precessional spin current magnetic layer has a circular shape.

6. The magnetic device of claim 1 , wherein the precessional spin current magnetic layer has a non-circular shape.

7. The magnetic device of claim 1 , wherein an axis of the precessional spin current magnetic layer is offset from an axis of the free layer by an offset distance, and wherein a ratio of the offset distance to the first diameter is in the range of 0 to 0.4.

8. A magnetic device, comprising:

a magnetic reference layer in a first plane, the magnetic reference layer having a magnetization vector that is perpendicular to the first plane and having a fixed magnetization direction;

a non-magnetic tunnel barrier layer in a second plane and disposed over the magnetic reference layer;

a free magnetic layer having a first diameter and disposed in a third plane over the non-magnetic tunnel barrier layer, the free magnetic layer having a magnetization vector that is perpendicular to the third plane and having a magnetization direction that can switch between a first magnetization direction to a second magnetization direction, the magnetic reference layer, the non-magnetic tunnel barrier layer and the free magnetic layer forming a magnetic tunnel junction; and

a precessional spin current magnetic layer having a second diameter that is less than the first diameter and a center that is offset relative to a center of the free magnetic layer, the precessional spin current magnetic layer disposed in a fourth plane that is physically separated from the free magnetic layer and coupled to the free magnetic layer by a filter coupling layer that may induce ferromagnetic or antiferromagnetic coupling between the free magnetic layer and the filter layer.

9. The magnetic device of claim 8 , wherein the second diameter is in the range of 5 nm to 100 nm.

10. The magnetic device of claim 8 , wherein a ratio of the second diameter to the first diameter is in the range of 0.2 to 0.9.

11. The magnetic device of claim 8 , wherein the precessional spin current magnetic layer is formed from Co x Fe y B z , where y is in the range 40% to 70%, z is in the range 18% to 21%, and x+y+z=100%.

12. The magnetic device of claim 8 , wherein the precessional spin current magnetic layer has a circular shape.

13. The magnetic device of claim 8 , wherein the precessional spin current magnetic layer has a non-circular shape.

14. The magnetic device of claim 8 , wherein an axis of the precessional spin current magnetic layer is offset from an axis of the free magnetic layer by an offset distance, and wherein a ratio of the offset distance to the first diameter is in the range of 0 to 0.4.

15. A method for manufacturing a magnetic device comprising the steps of:

providing a magnetic tunnel junction including a magnetic reference layer, a non-magnetic tunnel barrier layer, and a free magnetic layer;

depositing a filter coupling layer over the free magnetic layer;

depositing a precessional spin current magnetic layer over the filter coupling layer;

forming a partial pillar that includes the precessional spin current magnetic layer;

depositing a hard mask layer over the precessional spin current magnetic layer;

forming a pillar that includes the precessional spin current magnetic layer, the filter coupling layer, the free magnetic layer, the non-magnetic tunnel barrier layer, and the magnetic reference layer such that the precessional spin current magnetic layer has a central axis that is offset from a central axis of the free magnetic layer; and

depositing an electrical contact layer over the precessional spin current layer.