Ferromagnets as pure spin current generators and detectors

1. A spintronics device, comprising:

a ferromagnetic metal layer;

a magnetic dielectric layer, wherein the ferromagnetic metal layer is disposed on the magnetic dielectric layer;

a substrate, wherein the magnetic dielectric layer is disposed between the substrate and the ferromagnetic metal layer;

a positive electrode disposed on a first surface portion of the ferromagnetic metal layer; and

a negative electrode disposed on a second surface portion of the ferromagnetic metal layer.

2. The spintronics device of claim 1 , wherein the magnetic dielectric layer comprises a ferrimagnetic dielectric, a ferromagnetic dielectric, or an antiferromagnetic dielectric.

3. The spintronics device of claim 1 , wherein the magnetic dielectric layer comprises Y 3 Fe 5 O 12 (YIG).

4. The spintronics device of claim 1 , wherein the ferromagnetic metal layer comprises at least one of cobalt, iron, nickel, or alloys thereof.

5. The spintronics device of claim 4 , wherein the ferromagnetic metal layer comprises permalloy.

6. The spintronics device of claim 1 , wherein the magnetic dielectric layer comprises a thickness in the range of about 10 nm to about 1 mm, and the ferromagnetic metal layer comprises a thickness in the range of about 3 nm to about 30 nm.

7. A spintronics system, comprising:

a spintronics device comprising

a ferromagnetic metal layer,

a magnetic dielectric layer, wherein the ferromagnetic metal layer is disposed on the magnetic dielectric layer,

a substrate, wherein the magnetic dielectric layer is disposed between the substrate and the ferromagnetic metal layer,

a positive electrode disposed on a first surface portion of the ferromagnetic metal layer, and

a negative electrode disposed on a second surface portion of the ferromagnetic metal layer; and

a magnetic field source for providing magnetic field to the spintronics device and located to control the magnetic moment of the magnetic dielectric layer.

8. The spintronics system of claim 7 , further comprising a voltage measuring device in electrical communication with the positive and negative electrodes, wherein the magnetic dielectric layer comprises a spin current generator and the ferromagnetic metal layer comprises a spin current detector.

9. The spintronics system of claim 7 , further comprising a current source in electrical communication with the positive and negative electrodes, wherein the magnetic dielectric layer comprises a spin current detector and the ferromagnetic metal layer comprises a spin current generator.

10. The spintronics system of claim 7 , wherein the magnetic dielectric layer comprises a ferrimagnetic dielectric, a ferromagnetic dielectric, or an antiferromagnetic dielectric.

11. The spintronics system of claim 7 , wherein the magnetic dielectric layer comprises Y 3 Fe 5 O 12 (YIG).

12. The spintronics system of claim 7 , wherein the ferromagnetic metal layer comprises at least one of cobalt, iron, nickel, or alloys thereof.

13. The spintronics system of claim 12 , wherein the ferromagnetic metal layer comprises permalloy.

14. The spintronics system of claim 7 , further comprising a heat source on the ferromagnetic metal layer that forms a temperature gradient across at least a portion of the magnetic dielectric layer.

15. The spintronics system of claim 7 , further comprising a thermocouple connected to the magnetic dielectric layer and configured to measure a temperature difference at least across the magnetic dielectric layer.

16. The spintronics system of claim 7 , further comprising a microwave source that provides microwaves to the spintronics device at a resonance frequency of the magnetic dielectric layer and located such that the magnetic dielectric layer generates spin carriers.

17. A method of making a spintronics device, comprising:

forming a magnetic dielectric layer;

forming a ferromagnetic metal layer on the magnetic dielectric layer;

forming a positive electrode on a first surface portion of the ferromagnetic metal layer; and

forming a negative electrode on a second surface portion of the ferromagnetic metal layer.

18. The spintronics system of claim 7 further comprising a cold sink on a bottom surface of the spintronics device.

19. The spintronics system of claim 7 , wherein the magnetic moment of the magnetic dielectric determines spin orientation in a pure spin current when the magnetic dielectric is used as a spin current generator.

20. The spintronics system of claim 7 , wherein the magnetic moment of the magnetic dielectric controls a spin current absorption and reflection when the magnetic dielectric is used as a spin current detector.

21. The spintronics system of claim 20 , wherein the spin current absorption and reflection are controlled at an interface between the ferromagnetic layer and the magnetic dielectric layer.