Metal-insulator-metal near-field transducer for heat-assisted magnetic recording
Disclosed herein are embodiments of a heat-assisted magnetic recording (HAMR) device comprising a waveguide and a near-field transducer (NFT) coupled to the waveguide. The NFT comprises a core layer comprising an insulator, a first metal layer adjacent to the core layer, and a second layer adjacent to the first metal layer, wherein the second layer comprises a material that is substantially mechanically and thermally stable and thereby functions as a hard jacket to mitigate deformation of the NFT. The first metal layer may comprise a plasmonic metal, such as gold. The second layer may comprise tungsten, chromium, or a dielectric material.
1. A heat-assisted magnetic recording (HAMR) device, comprising:
a waveguide;
a near-field transducer coupled to the waveguide, the near-field transducer comprising:
a core layer comprising an insulator,
a first metal layer adjacent to the core layer, and
a second layer adjacent to the first metal layer, wherein the second layer comprises tungsten, chromium, SiC, or a dielectric material;
an anti-reflective trench between the waveguide and the near-field transducer; and
at least one mirror adjacent to the second layer of the near-field transducer.
2. The HAMR device recited in claim 1 , wherein the first metal layer comprises a plasmonic metal, and wherein a thickness of the first metal layer is no less than a skin depth of the plasmonic metal.
3. The HAMR device recited in claim 1 , wherein the first metal layer comprises a plasmonic metal, and wherein a thickness of the first metal layer is substantially equal to a skin depth of the plasmonic metal.
4. The HAMR device recited in claim 1 , wherein the first metal layer comprises gold or a gold alloy.
5. The HAMR device recited in claim 4 , wherein a thickness of the first metal layer is between approximately 30 nm and 100 nm.
6. The HAMR device recited in claim 1 , wherein the first metal layer comprises Pd, Pt, Rh, Ir, Ru, Au, Cu, Al, Ag, or an alloy of two or more of Pd, Pt, Rh, Ir, Ru, Au, Cu, Ag, and Al.
7. The HAMR device recited in claim 1 , wherein a thermal expansion coefficient of the second layer is lower than a thermal expansion coefficient of the core layer.
8. The HAMR device recited in claim 1 , wherein a thermal expansion coefficient of the core layer is substantially matched by a thermal expansion coefficient of a combination of the first metal layer and the second layer.
9. The HAMR device recited in claim 1 , wherein a thickness of the second layer is at least 2 nm.
10. The HAMR device recited in claim 1 , wherein the waveguide and near-field transducer are in a direct-fire configuration.
11. The HAMR device recited in claim 1 , wherein the at least one mirror is also adjacent to the anti-reflective trench.
12. The HAMR device recited in claim 11 , wherein the at least one mirror has an offset lip.
13. The HAMR device recited in claim 11 , wherein the first metal layer extends a first distance to an air-bearing surface (ABS) of the HAMR device, and the second layer extends a second distance toward the ABS of the HAMR device, the second distance being less than the first distance, and further comprising a dielectric layer extending from an end of the second layer to the ABS of the HAMR device.
14. The HAMR device recited in claim 1 , wherein the at least one mirror has an offset lip.
15. The HAMR device recited in claim 1 , wherein the first metal layer extends a first distance to an air-bearing surface (ABS) of the HAMR device, and the second layer extends a second distance toward the ABS of the HAMR device, the second distance being less than the first distance, and further comprising a dielectric layer extending from an end of the second layer to the ABS of the HAMR device.
16. The HAMR device recited in claim 1 , wherein a shape of at least a portion of the core layer viewed from an air-bearing surface of the HAMR device is triangular.
17. The HAMR device recited in claim 1 , wherein at least a portion of the core layer viewed from an air-bearing surface of the HAMR device has an L-shape, a C-shape, an E-shape, or a tapered shape.
18. A magnetic storage device comprising:
a write pole; and
the HAMR device recited in claim 1 .