Heat-assisted magnetic recording head with a multilayer plasmonic disk

1. A heat-assisted magnetic recording head comprising:

a waveguide; and

a near-field transducer comprising a plasmonic disk disposed proximal to the waveguide, the plasmonic disk comprising:

a first plasmonic layer coupled to the waveguide;

a second plasmonic layer disposed distal to the waveguide relative to the first plasmonic layer; and

a middle layer disposed between the first plasmonic layer and the second plasmonic layer,

wherein a primary metal of the first plasmonic layer is different than a primary metal of the middle layer, and

wherein a primary metal of the second plasmonic layer is different than the primary metal of the middle layer.

2. The heat-assisted magnetic recording head of claim 1 , wherein the primary metal of the middle layer comprises at least one of iridium, rhodium, tantalum, tungsten, or ruthenium.

3. The heat-assisted magnetic recording head of claim 1 , wherein the primary metal of the middle layer comprises at least 90 atomic percent of the middle layer.

4. The heat-assisted magnetic recording head of claim 1 , wherein the primary metal of the first plasmonic layer comprises a plasmonic metal comprising at least one of gold, silver, ruthenium, copper, aluminum, or rhodium.

5. The heat-assisted magnetic recording head of claim 1 , wherein the primary metal of the second plasmonic layer comprises a plasmonic metal comprising at least one of gold, silver, ruthenium, copper, aluminum, or rhodium.

6. The heat-assisted magnetic recording head of claim 1 , wherein the primary metal of the first plasmonic layer comprises at least 90 atomic percent of the first plasmonic layer.

7. The heat-assisted magnetic recording head of claim 1 , wherein the primary metal of the second plasmonic layer comprises at least 90 atomic percent of the second plasmonic layer.

8. The heat-assisted magnetic recording head of claim 1 , wherein the primary metal of the first plasmonic layer is the same as the primary metal of the second plasmonic layer.

9. A heat-assisted magnetic recording head comprising:

a waveguide; and

a near-field transducer comprising a plasmonic disk disposed proximal to the waveguide, the plasmonic disk comprising:

a first plasmonic layer coupled to the waveguide;

a second plasmonic layer disposed distal to the waveguide relative to the first plasmonic layer; and

a middle layer disposed between the first plasmonic layer and the second plasmonic layer,

wherein the first plasmonic layer comprises:

an outer surface that is coupled to the waveguide;

a first segment that is substantially parallel to and coupled to the waveguide; and

a second segment that deviates from being substantially parallel to the waveguide.

10. The heat-assisted magnetic recording head of claim 9 , wherein the second segment of the first plasmonic layer is substantially orthogonal to the waveguide on a side of the plasmonic disk that is opposite the waveguide.

11. The heat-assisted magnetic recording head of claim 9 ,

wherein the second segment is disposed at the front of the plasmonic disk relative to a media-facing surface of the heat-assisted magnetic recording head, and

wherein a contour of the second segment curves toward the media-facing surface.

12. The heat-assisted magnetic recording head of claim 9 ,

wherein the second segment is disposed along an outer edge of the plasmonic disk, and

wherein the outer edge encloses and defines dimensions of the plasmonic disk in a plane that is defined by a media-facing dimension and a cross-track dimension of the heat-assisted magnetic recording head.

13. The heat-assisted magnetic recording head of claim 9 , wherein the outer surface of the first plasmonic layer is further coupled to a front cladding layer, the front cladding layer disposed proximal to the media-facing surface and in front of the plasmonic disk relative to the media-facing surface.

14. The heat-assisted magnetic recording head of claim 9 , wherein the outer surface of the first plasmonic layer is further coupled to a rear cladding layer, the rear cladding layer disposed behind the plasmonic disk relative to the media-facing surface.

15. The heat-assisted magnetic recording head of claim 9 , wherein the middle layer comprises:

a first segment that is substantially parallel to and coupled to the first segment of the first plasmonic layer; and

a second segment that is disposed along a contour of the second segment of the first plasmonic layer and is coupled to the second segment of the first plasmonic layer.

16. The heat-assisted magnetic recording head of claim 15 , wherein an up-track surface of the second plasmonic layer is disposed along and coupled to the middle layer.

17. The heat-assisted magnetic recording head of claim 16 ,

wherein the second plasmonic layer further comprises a down-track surface that is opposite the second plasmonic layer from and substantially parallel to the first segment of the middle layer, and

wherein the up-track surface of the second plasmonic layer is coupled to the down-track surface of the second plasmonic layer at a down-track surface of the plasmonic disk.

18. The heat-assisted magnetic recording head of claim 16 , wherein a volume of the second plasmonic layer is bound by the up-track surface of the second plasmonic layer and the down-track surface of the second plasmonic layer.

19. The heat-assisted magnetic recording head of claim 15 , the near-field transducer further comprising a near-field emitter disposed in a down-track direction relative to the plasmonic disk, the near-field emitter comprising:

a peg configured to produce a hot spot on a proximal magnetic disk, the peg disposed proximal to a media-facing surface of the heat-assisted magnetic recording head; and

an anchor disk disposed behind the peg relative to the media-facing surface,

wherein a down-track surface of the plasmonic disk is coupled to an up-track surface of the anchor disk, the down-track surface of the plasmonic disk comprising:

a down-track surface of the second plasmonic layer;

a down-track surface of the second segment of the middle layer; and

a down-track surface of the second segment of the first plasmonic layer.