Spin current generator for STT-MRAM or other spintronics applications
View Patent ↗Spin current generators and systems and methods for employing spin current generators. A spin current generator may be configured to generate a spin current polarized in one direction, or a spin current selectively polarized in two directions. The spin current generator may by employed in spintronics applications, wherein a spin current is desired.
1. A spin current generator comprising:
at least one structure comprising a ferromagnetic layer and a nonmagnetic layer; and
at least one gate configured to selectively apply a voltage to the at least one structure,
wherein the spin current generator is configured to output a current.
2. The spin current generator, as set forth in claim 1 , wherein the nonmagnetic layer is formed directly on the ferromagnetic layer, and wherein the at least one structure further comprises an antiferromagnetic layer, wherein the ferromagnetic layer is formed directly on the antiferromagnetic layer.
3. The spin current generator, as set forth in claim 1 , wherein the at least one structure comprises an insulative material formed adjacent to the ferromagnetic layer and the nonmagnetic layer.
4. The spin current generator, as set forth in claim 1 , wherein the at least one structure comprises a heater material formed adjacent to the ferromagnetic layer and the nonmagnetic layer.
5. The spin current generator, as set forth in claim 1 , wherein the at least one structure comprises a piezoelectric material formed adjacent to the ferromagnetic layer and the nonmagnetic layer.
6. The spin current generator, as set forth in claim 1 , wherein the at least one gate comprises a transistor.
7. The spin current generator, as set forth in claim 1 , wherein the spin current generator configured to generate a current having a spin polarity and further configured to generate an unpolarized current.
8. The spin current generator, as set forth in claim 1 , wherein the at least one structure comprises:
a first structure comprising a first ferromagnetic layer and a first nonmagnetic layer formed directly on the first ferromagnetic layer; and
a second structure comprising a second ferromagnetic layer and a second nonmagnetic layer formed directly on the second ferromagnetic layer,
wherein the first ferromagnetic layer and the second ferromagnetic layer are oppositely magnetized.
9. The spin current generator, as set forth in claim 8 , wherein the at least one gate comprises a first transistor coupled to the first structure and a second transistor coupled to the second structure.
10. The spin current generator, as set forth in claim 8 , wherein the spin current generator is configured to generate a spin current having a polarity parallel to a magnetization of the first ferromagnetic layer, and further configured to generate a spin current having a polarity parallel to a magnetization of the second ferromagnetic layer.
11. The spin current generator, as set forth in claim 1 , wherein the spin current generator is configured to generate a spin current having a first polarity, and further configured to generate a spin current having a second polarity.
12. A system comprising:
a programmable structure; and
a spin current generator configured to generate a spin current through the programmable structure.
13. The system, as set forth in claim 12 , wherein the programmable structure comprises a memory cell.
14. The system, as set forth in claim 13 , wherein the memory cell comprise a spin torque transfer magnetic random access memory cell having a free layer and a pinned layer.
15. The system, as set forth in claim 14 , wherein the spin current generator is configured to polarize the free layer to a first polarity, and further configured to polarize the free layer to a second polarity, opposite the first polarity.
16. The system, as set forth in claim 12 , wherein the spin current generator is configured to generate a spin current having a first polarity, and further configured to generate a spin current having a second polarity, opposite the first polarity.
17. The system, as set forth in claim 12 , wherein the spin current generator comprises:
a first structure configured to generate a spin current having a first polarity; and
a second structure, parallel to the first structure, and configured to generate a spin current having a second polarity, opposite the first polarity.
18. The system, as set forth in claim 17 , comprising one or more gates configured to selectively transmit current through either the first structure or the second structure.
19. The system, as set forth in claim 17 , wherein:
the first structure comprises a first ferromagnetic layer and a first nonmagnetic layer formed directly on the first ferromagnetic layer; and
the second structure comprises a second ferromagnetic layer and a second nonmagnetic layer formed directly on the second ferromagnetic layer,
wherein the first ferromagnetic layer and the second ferromagnetic layer are oppositely magnetized.
20. The system, as set forth in claim 12 , wherein the spin current generator comprises a piezoelectric material.
21. The system, as set forth in claim 12 , wherein the spin current generator comprises a heater material.
22. The system, as set forth in claim 21 , wherein the spin current generator comprises a ferromagnetic layer, and wherein the heater material is configured to heat the ferromagnetic layer to reduce its spin-polarization efficiency.
23. The system, as set forth in claim 12 , wherein the programmable structure comprises a plurality of memory cells coupled in series to one another, and wherein the spin current generator is configured to generate a spin current through each of the plurality of memory cells.
24. The system, as set forth in claim 23 , wherein the spin current generator is configured to generate a spin current through each of the plurality of memory cells, simultaneously.
25. A method of operating a device comprising:
transmitting, from a spin current generator, a first current having a first polarity through a structure of the device in a first direction; and
transmitting, from the spin current generator, a second current having a second polarity through the structure in the first direction, wherein the first polarity is opposite the second polarity.
26. The method, as set forth in claim 25 , wherein transmitting the first current sets the structure into a first state, and wherein transmitting the second current sets the structure into a second state.
27. The method, as set forth in claim 25 , wherein transmitting through the structure comprises transmitting through a memory device.
28. The method, as set forth in claim 27 , wherein transmitting the first current programs the memory device into a first state, and wherein transmitting the second current programs the memory device into a second state.
29. The method, as set forth claim 28 , wherein transmitting the first current programs the memory device into a low resistance state, and wherein transmitting the second current programs the memory device into a high resistance state.
30. A method of operating a device comprising:
transmitting, from a spin current generator, a first current having a polarity through a structure of the device in a first direction; and
transmitting, from the spin current generator, a second current having a non polarity through the structure in the first direction.
31. The method, as set forth in claim 30 , wherein transmitting the first current sets the structure into a first state, and wherein transmitting the second current sets the structure into a second state.