Surface-plasmon opto-magnetic field enhancement for all-optical magnetization switching
A magneto-plasmonic nanostructure is disclosed. The structure includes a substrate, and a magneto-plasmonic stack, comprising a nano-sized plasmonic resonator, a nanomagnet, and a capping layer, wherein the nano-sized plasmonic resonator is configured to receive circularly polarized light at an intensity to thereby increase normal component of plasmon-generated opto-magnetic field, H OM,z , at least at the interface of one of i) the nano-sized plasmonic resonator and the nanomagnet, or ii) the nanomagnet and the capping layer, whereby the H OM,z direction is perpendicular to the rotational direction of the circularly polarized light and the nanomagnets in the magneto-plasmonic stack switches its magnetic moment in response to a change of the H OM,z direction in response to a change of the rotational direction of the circularly polarized light.
1. A magneto-plasmonic nanostructure, comprising:
a substrate, and
a magneto-plasmonic stack, comprising:
a nano-sized plasmonic resonator,
a nanomagnet, and
a capping layer,
wherein the nano-sized plasmonic resonator is configured to receive circularly polarized light at an intensity to thereby increase normal component of plasmon-generated opto-magnetic field, H OM,z , at least at the interface of one of i) the nano-sized plasmonic resonator and the nanomagnet, or ii) the nanomagnet and the capping layer, whereby the H OM,z direction is perpendicular to the rotational direction of the circularly polarized light and the nanomagnets in the magneto-plasmonic stack switches its magnetic moment in response to a change of the H OM,z direction in response to a change of the rotational direction of the circularly polarized light.
2. The magneto-plasmonic nanostructure of claim 1 , wherein the substrate is made of an optically transparent material.
3. The magneto-plasmonic nanostructure of claim 2 , wherein the optically transparent material is selected from the group consisting essentially of MgO and c-sapphire.
4. The magneto-plasmonic nanostructure of claim 1 , wherein the nano-sized plasmonic resonator is selected from the group consisting essentially of TiN and ZrN.
5. The magneto-plasmonic nanostructure of claim 1 , wherein the nanomagnet is one of a ferromagnet, a ferrimagnet or an antiferromagnet having magnetic perpendicular anisotropy.
6. The magneto-plasmonic nanostructure of claim 5 , wherein the nanomagnet selected from the group consisting essentially of Bi-substituted iron garnet (BIG) and Gadolinium Iron Cobalt (GdFeCo).
7. The magneto-plasmonic nanostructure of claim 1 , wherein the capping layer is Si 3 N 4 .
8. The magneto-plasmonic nanostructure of claim 1 , wherein the magneto-plasmonic stack is between about 10 nm and 20 nm.
9. The magneto-plasmonic nanostructure of claim 8 , wherein the enhancement of the H OM is between about 3 times to about 10 times as compared to a structure without the nano-sized plasmonic resonator.
10. The magneto-plasmonic nanostructure of claim 1 , wherein the wavelength of the circular polarized light is between 660 nm and 740 nm.
11. A system of writing to and read from a magneto-plasmonic nanostructure, comprising:
a magneto-plasmonic write arrangement, comprising:
a polarizer configured to provide a focused circularly polarized light with selective rotation;
a magneto-plasmonic structure configured to receive the focused circularly polarized light, the magneto-plasmonic structure comprising:
a substrate, and
a magneto-plasmonic stack, comprising:
a nano-sized plasmonic resonator,
a nanomagnet, and
a capping layer,
wherein the nano-sized plasmonic resonator is configured to receive circularly polarized light at an intensity to thereby increase normal component of plasmon-generated opto-magnetic field, H OM,z , at least at the interface of one of i) the nano-sized plasmonic resonator and the nanomagnet, or ii) the nanomagnet and the capping layer, whereby the H OM,z direction is perpendicular to the rotational direction of the circularly polarized light and the nanomagnets in the magneto-plasmonic stack switches its magnetic moment in response to a change of the H OM,z direction in response to a change of the rotational direction of the circularly polarized light,
whereby the magnetic moment direction specifies a bit value held in the magneto-plasmonic structure; and
a magneto-plasmonic read arrangement, configured to receive the plasmon-generated opto-magnetic field, H OM,z , and thereby determine the direction of the H OM as a bit value of the magneto-plasmonic structure.
12. The system of claim 11 , wherein the substrate is made of an optically transparent material dielectric.
13. The system of claim 12 , wherein the optically transparent material is selected from the group consisting essentially of MgO and c-sapphire.
14. The system of claim 11 , wherein the nano-sized plasmonic resonator is selected from the group consisting essentially of TiN and ZrN.
15. The system of claim 11 , wherein the nanomagnet is one of a ferromagnet, a ferrimagnet or an antiferromagnet having magnetic perpendicular anisotropy.
16. The system of claim 15 , wherein the nanomagnet selected from the group consisting essentially of Bi-substituted iron garnet (BIG) and Gadolinium Iron Cobalt (GdFeCo).
17. The system of claim 11 , wherein the capping layer is Si 3 N 4 .
18. The system of claim 11 , wherein the magneto-plasmonic stack is between about 10 nm and 20 nm.
19. The system of claim 18 , wherein the enhancement of the H OM is between about 3 times to about 10 times as compared to a structure without the nano-sized plasmonic resonator.
20. The system of claim 11 , wherein the wavelength of the circular polarized light is between 660 nm and 740 nm.