Thermally stable Au alloys as a heat diffusion and plasmonic underlayer for heat-assisted magnetic recording (HAMR) media
According to one embodiment, a magnetic medium includes a plasmonic underlayer having an Au alloy, where the Au alloy includes one or more alloying components that are substantially immiscible in Au; and a magnetic recording layer above the plasmonic underlayer. According to another embodiment, a magnetic medium, includes a multilayered plasmonic underlayer; and a magnetic recording layer above the multilayered plasmonic underlayer.
1. A magnetic medium, comprising:
a first plasmonic underlayer comprising a first Au alloy, wherein the first Au alloy comprises one or more alloying components that are substantially immiscible in Au;
a second plasmonic underlayer comprising a second Au alloy, wherein the second Au alloy comprises one or more alloying components that are substantially immiscible in Au; and
a magnetic recording layer above the plasmonic underlayers,
wherein at least of one of the alloying components of the first Au alloy is different than at least one of the alloying components of the second Au alloy,
wherein the first and second plasmonic underlayers each have a thermal conductivity of at least about 30 W/m-K.
2. The magnetic medium as recited in claim 1 , wherein the one or more alloying components of the first Au alloy are selected from the group consisting of: Rh, Mo, W, Co, Pt, Ru, B and Ni.
3. The magnetic medium as recited in claim 1 , wherein the one or more alloying components of the first Au alloy are inhomogeneously distributed within the first plasmonic underlayer.
4. The magnetic medium as recited in claim 1 , wherein the one or more alloying components of the first Au alloy or the second Au alloy comprise Rh in an amount from about 0.5 at % to about 8 at %.
5. The magnetic medium as recited in claim 1 , wherein the one or more alloying components of the first Au alloy or the second Au alloy comprise Ni in an amount from about 0.5 at % to about 25 at %.
6. The magnetic medium as recited in claim 1 , wherein the one or more alloying components of the first Au alloy or the second Au alloy comprise W in an amount from about 0.5 at % to about 8 at %.
7. The magnetic medium as recited in claim 1 , wherein the one or more alloying components of the first Au alloy or the second Au alloy comprise Mo in an amount from about 0.5 at % to about 8 at %.
8. A magnetic medium, comprising:
a multilayered plasmonic underlayer; and
a magnetic recording layer above the multilayered plasmonic underlayer,
wherein the multilayered plasmonic underlayer comprises at least one plasmonic layer comprising a first Au alloy, and at least one plasmonic layer comprising a second Au alloy, wherein the first Au alloy is different than the second Au alloy.
9. The magnetic medium as recited in claim 1 , wherein the one or more alloying components of the first Au alloy comprise Rh in an amount of about 1.2 at % or less, and wherein the first plasmonic underlayer has a thermal conductivity of about 100 W/m-K or greater.
10. The magnetic medium as recited in claim 1 , wherein the one or more alloying components of the first Au alloy comprise Ni in an amount of about 3.8 at % or less, and wherein the first plasmonic underlayer has a thermal conductivity of about 100 W/m-K or greater.
11. The magnetic medium of claim 1 , wherein the one or more alloying components of the second Au alloy are selected from the group consisting of: Rh, Mo, W, Co, Pt, Ru, B and Ni.
12. The magnetic medium as recited claim 1 , wherein the one or more alloying components of the first Au alloy and the second Au alloy substantially surround Au grain boundaries.
13. The magnetic medium as recited claim 1 , wherein the one or more alloying components of the first Au alloy and the second Au alloy have a melting point greater than the melting point of Au.
14. The magnetic medium as recited in claim 1 , wherein a combined thickness of the first and second plasmonic underlayers is in a range from 10 nm to 100 nm.
15. A magnetic medium, comprising:
a plasmonic underlayer comprising an Au alloy, wherein the Au alloy comprises one or more alloying components that are substantially immiscible in Au;
a second plasmonic underlayer comprising a second gold alloy, wherein the second gold alloy comprises one or more alloying components that are substantially immiscible in Au; and
a magnetic recording layer above the plasmonic underlayers,
wherein the one or more alloying components in the second gold alloy are selected from a group consisting of: Rh, Mo, W, Co, Pt, Ru, B and Ni, with the proviso that the one or more alloying components of the second gold alloy are different than the one or more alloying components in the gold alloy.
16. The magnetic medium as recited in claim 1 , wherein the first plasmonic underlayer and the second plasmonic underlayer each have a surface roughness of less than 1 nm.
17. The magnetic medium as recited in claim 1 , wherein one of the plasmonic underlayers has a physical characteristic of being resistant to grain growth and morphological change at temperatures greater than about 100° C. to about 400° C.
18. The magnetic medium as recited in claim 8 , wherein each plasmonic layer of the multilayered plasmonic underlayer has a thermal conductivity of at least about 30 W/m-K.
19. The magnetic medium of claim 8 , wherein the first Au alloy and the second Au alloy each have one or more alloying components that are substantially immiscible in Au.
20. The magnetic medium as recited in claim 19 , wherein the one or more alloying components in the first Au alloy and the second Au alloy are independently selected from the group consisting of: Rh, Mo, W, Co, Pt, Ru, B and Ni.
21. The magnetic medium as recited in claim 8 , wherein the multilayered plasmonic underlayer comprises at least one plasmonic layer of pure gold.
22. The magnetic medium as recited in claim 21 , wherein the plasmonic layer of pure gold is positioned between the plasmonic layer comprising the first Au alloy and the plasmonic layer comprising the second Au alloy.
23. The magnetic medium as recited in claim 8 , wherein a total thickness of the multilayered plasmonic underlayer is between about 10 to about 100 nm.
24. A magnetic data storage system, comprising:
at least one magnetic head,
the magnetic medium as recited in claim 1 ;
a drive mechanism for passing the magnetic medium over the at least one magnetic head; and
a controller electrically coupled to the at least one magnetic head for controlling operation of the at least on magnetic head.
25. The magnetic data storage system as recited in claim 24 , wherein the at least one magnetic head further comprises:
a near field transducer;
an optical waveguide configured to illuminate the near field transducer; and
a write pole.