All-spin logic devices
Illustrative embodiments of all-spin logic devices, circuits, and methods are disclosed. In one embodiment, an all-spin logic device may include a first nanomagnet, a second nanomagnet, and a spin-coherent channel extending between the first and second nanomagnets. The spin-coherent channel may be configured to conduct a spin current from the first nanomagnet to the second nanomagnet to determine a state of the second nanomagnet in response to a state of the first nanomagnet.
1. An all-spin logic device comprising:
a first nanomagnet;
a second nanomagnet; and
a spin-coherent channel extending between the first and second nanomagnets, the spin-coherent channel configured to conduct a spin current from the first nanomagnet to the second nanomagnet to determine a state of the second nanomagnet in response to a state of the first nanomagnet.
2. The all-spin logic device of claim 1 , wherein the first and second nanomagnets have identical switching characteristics.
3. The all-spin logic device of claim 1 , further comprising a tunnel barrier disposed at an interface between the spin-coherent channel and one of the first and second nanomagnets.
4. The all-spin logic device of claim 1 , wherein the second nanomagnet comprises:
a free layer having an easy axis; and
a fixed layer having an easy axis, the easy axis of the fixed layer being perpendicular to the easy axis of the free layer.
5. The all-spin logic device of claim 1 , wherein the first and second nanomagnets are each electrically coupled to one un-clocked supply voltage.
6. The all-spin logic device of claim 5 , wherein the second nanomagnet has a greater spin-torque conductance relative to the spin-coherent channel than the first nanomagnet.
7. The all-spin logic device of claim 5 , wherein the spin-coherent channel comprises a ground terminal positioned closer to the first nanomagnet than to the second nanomagnet.
8. The all-spin logic device of claim 1 , wherein the second nanomagnet is electrically coupled to a floating voltage.
9. The all-spin logic device of claim 1 , wherein the second nanomagnet is grounded.
10. The all-spin logic device of claim 1 , wherein the first and second nanomagnets each have an energy barrier of at least one-quarter electron-volt and each comprise less than 10 6 Bohr magnetons.
11. An all-spin logic circuit comprising:
a first nanomagnet having an input side and an output side;
a second nanomagnet having an input side and an output side;
a third nanomagnet having an input side and an output side;
a first spin-coherent channel configured to conduct a spin current generated from the input side of the first nanomagnet to the output side of the second nanomagnet; and
a second spin-coherent channel configured to conduct a spin current generated from the input side of the second nanomagnet to the output side of the third nanomagnet.
12. The all-spin logic circuit of claim 11 , wherein the first, second, and third nanomagnets have identical switching characteristics.
13. The all-spin logic circuit of claim 11 , further comprising a third spin-coherent channel configured to conduct a spin current generated from the input side of the third nanomagnet to the output side of the first nanomagnet.
14. The all-spin logic circuit of claim 11 , wherein the output sides of the first, second, and third nanomagnets each have a greater spin-torque conductance than the input sides of the first, second, and third nanomagnets.
15. The all-spin logic circuit of claim 11 , wherein:
the first spin-coherent channel comprises a ground terminal positioned closer to the input side of the first nanomagnet than to the output side of the second nanomagnet; and
the second spin-coherent channel comprises a ground terminal positioned closer to the input side of the second nanomagnet than to the output side of the third nanomagnet.
16. The all-spin logic circuit of claim 11 , wherein the first and second spin-coherent channels are separated by an isolation layer.
17. The all-spin logic circuit of claim 11 , wherein the first, second, and third nanomagnets are each electrically coupled to one un-clocked supply voltage.
18. A method comprising:
applying a voltage to a first nanomagnet to generate a first spin current in response to a magnetization direction of the first nanomagnet; and
routing the first spin current along a first spin-coherent channel to a second nanomagnet to determine a magnetization direction of the second nanomagnet.
19. The method of claim 18 , wherein the magnetization direction of the second nanomagnet does not determine the magnetization direction of the first nanomagnet.
20. The method of claim 18 , further comprising:
applying a voltage to a third nanomagnet to generate a second spin current in response to a magnetization direction of the third nanomagnet; and
routing the second spin current along the first spin-coherent channel to the second nanomagnet to determine the magnetization direction of the second nanomagnet in response to a superposition of the first and second spin currents.
21. The method of claim 18 , further comprising:
applying a voltage to the second nanomagnet to generate a second spin current in response to the magnetization direction of the second nanomagnet; and
routing the second spin current along a second spin-coherent channel to a third nanomagnet to determine a magnetization direction of the third nanomagnet.
22. The method of claim 21 , further comprising:
applying a voltage to the third nanomagnet to generate a third spin current in response to the magnetization direction of the third nanomagnet; and
routing the third spin current along a third spin-coherent channel to the first nanomagnet to determine the magnetization direction of the first nanomagnet.
23. The method of claim 21 , wherein applying a voltage to the first nanomagnet and applying a voltage to the second nanomagnet comprise applying one un-clocked supply voltage to both the first and second nanomagnets.
24. The method of claim 18 , further comprising applying a clocked supply voltage to a fixed layer of the second nanomagnet to place a free layer of the second nanomagnet in a neutral state while receiving the first spin current from the first spin-coherent channel.
25. The method of claim 18 , further comprising applying a floating voltage to the second nanomagnet while receiving the first spin current from the first spin-coherent channel.
26. The method of claim 18 , further comprising grounding the second nanomagnet while receiving the first spin current from the first spin-coherent channel.
27. The method of claim 26 , wherein the magnetization direction of the second nanomagnet oscillates with the magnetization direction of the first nanomagnet.