Heat assisted magnetic recording (HAMR) head with heat sink material adjacent to waveguide

Abstract

The present invention is entitled "Heat-Assisted Magnetic Recording (HAMR) Head with Heat Sink Material Adjacent to Waveguide". The present invention discloses a heat-assisted magnetic recording (HAMR) head having a gas bearing slider and a main magnetic pole supporting a near-field transducer (NFT). A first heat sink material is located on the cross-track side of the main pole, and a second heat sink material is located on the cross-track side of the waveguide. The second heat sink material can be in contact with the first heat sink material, and a high thermal conductivity heat shunt can interconnect the NFT with the first heat sink material and the second heat sink material. Heat from the NFT output tip flows to the second heat sink material through the NFT and the heat shunt. An optically reflective material can be located between the waveguide and the second heat sink material to improve the optical efficiency of the NFT.

Description

Technical Field

[0001] The present invention relates generally to heat-assisted magnetic recording (HAMR) disk drives in which data is written while a magnetic recording layer on the disk is at an elevated temperature, and more particularly to an improved HAMR head. Background Art

[0002] In conventional magnetic recording, thermal instability of the magnetization stored in the recording medium can lead to loss of recorded data. To avoid this, a material with high magnetocrystalline anisotropy (K u ) medium. However, increasing K u It also increases the coercivity of the media, which can exceed the write field capability of the write head. Since the coercivity of the magnetic material of the recording layer is known to be temperature dependent, one proposed solution to the thermal stability problem is heat-assisted magnetic recording (HAMR), where high K u The magnetic recording material is locally heated during writing via the main pole to reduce the coercivity sufficient for writing, but where the coercivity / anisotropy is high enough to achieve thermal stability of the recorded bits at the ambient temperature of the disk drive (i.e., normal operating temperature or "room temperature" of about 15°C-30°C). In some proposed HAMR systems, the magnetic recording material is heated to near or above its Curie temperature. The recorded data is then read back at ambient temperature by a conventional magnetoresistive read head. HAMR disk drives have been proposed for conventional continuous media, where the magnetic recording material is a continuous layer on the disk, and for bit patterned media (BPM), where the magnetic recording material is patterned into discrete data islands or "bits."

[0003] One type of proposed HAMR disk drive uses a laser source and an optical waveguide coupled to a near-field transducer (NFT) for heating the recording material on the disk. A "near-field" transducer refers to "near-field optics" in which light is passed through an element having sub-wavelength characteristics and the light is coupled to a second element, such as a substrate of a magnetic recording medium, located a sub-wavelength distance from the first element. The NFT is typically located at the gas bearing surface (GBS) of a gas bearing slider that also supports the read / write head and rides or "files" above the disk surface.

[0004] An NFT with a generally triangular or trapezoidal output end is described in US 8705327 B2, assigned to the same assignee as the present patent application. In this NFT, evanescent waves generated at the surface of the waveguide couple to surface plasmons excited on the surface of the NFT and generate a strong optical near field at the vertex of the output end. Summary of the invention

[0005] In conventional HAMR heads, heat from the NFT causes deformation of the NFT. Heat can also cause the temperature in the main magnetic pole to rise. This increases the possibility of undesirable oxidation of the main pole at the GBS, which is also affected by the wear of the head protective outer coating. In order to improve head reliability, it is desirable to minimize the deformation of the NFT and the oxidation of the main pole by minimizing the heating of the NFT and the main pole. This will also reduce the thermal protrusion of the NFT caused by the heat originating from the NFT. It is also desirable to improve optical efficiency so that the waveguide mode is efficiently converted to the optical near field and the light is more confined at the apex of the NFT. This will improve the thermal gradient in the recording layer to increase the surface density, and reduce the laser power to reduce the power consumption of the laser.

[0006] In an embodiment of the present invention, a first heat sink material may be located on the cross-track side of the main pole, and an additional heat sink material is located on the cross-track side of the waveguide. The additional or second heat sink material further reduces the temperature of the NFT, and thus reduces the possibility of deformation of the NFT. The second heat sink is in contact with the NFT and the heat shunt so that heat from the output tip of the NFT flows through the NFT and the heat shunt to the second heat sink material. It reduces the temperature of the NFT and thus reduces the possibility of deformation of the NFT. The second heat sink is optionally connected to the first heat sink material on the cross-track side of the main pole to further reduce the temperature of the NFT. It can also reduce the temperature of the main pole, thereby reducing the possibility of oxidation of the main pole. In some embodiments, an optical reflective material may be located between the waveguide and the second heat sink material to improve the optical efficiency of the NFT.

[0007] For a more complete understanding of the nature and advantages of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a top view of a heat-assisted magnetic recording (HAMR) disk drive according to an embodiment of the present invention.

[0009] Figure 2 is a side cross-sectional view of a portion of a HAMR disk and a gas bearing slider used in a HAMR disk drive according to the prior art, the side cross-sectional view not being drawn to scale due to the difficulty in showing very small features.

[0010] Figure 3A is a side cross-sectional view of the layers of material making up the main and primary poles, near field transducer (NFT) and waveguide according to the prior art and shown relative to the recording layers on a disk.

[0011] Figure 3B is a perspective view of a main pole, primary pole, NFT, tapered waveguide, and heat sink material on the cross-track side of the main pole according to the prior art.

[0012] Figure 3C According to the existing technology Figure 3B An enlarged perspective view of a portion of FIG. 1 showing the connection of the thermal shunt to the NFT output tip with the heat sink material located on the cross-track side of the main pole.

[0013] Figure 4A is a gas bearing surface (GBS) view of an embodiment of the present invention and shows a second heat sink material located on the cross-track side of the waveguide.

[0014] Figure 4B is a gas bearing surface (GBS) view of an embodiment of the present invention and shows a second heat sink material located on the cross-track side of the waveguide and extending into contact with the return pole.

[0015] Figure 4C is a view of section 4C-4C, which is Figure 4B The XY plane shows a tapered waveguide with an overlying thermal shunt.

[0016] Figure 4D is a cross-sectional view, which is in the XY plane and shows an embodiment of the present invention with modifications to the heat diverter.

[0017] Figure 4E is a cross-sectional view, which is the XY plane and shows a modified embodiment of the present invention with a side heat sink layer at the GBS.

[0018] Figure 4F is a cross-sectional view, which is in the XY plane and shows an embodiment of the present invention where the side heat sink layer is recessed from the GBS.

[0019] Figure 5 GBS view of an embodiment of the invention having two optional features. DETAILED DESCRIPTION

[0020] Figure 1 FIG. 1 is a top view of a heat assisted recording (HAMR) disk drive 10 according to an embodiment of the present invention. Figure 1 , a HAMR disk drive 10 is depicted as having a disk 150 having a magnetic recording layer 31 of conventional continuous magnetic recording material arranged in radially spaced circular tracks 118. Only a few representative tracks 118 are shown near the inner and outer diameters of the disk 150. However, the recording layer may be a bit patterned media (BPM) layer having discrete data islands rather than a conventional continuous magnetic recording layer.

[0021] The HAMR disk drive 10 has a housing or base 112 that supports an actuator 130 and a drive motor for rotating a magnetic recording disk 150. The actuator 130 may be a voice coil motor (VCM) rotary actuator having a rigid actuator arm 131 and rotating about a pivot 132 (as shown by arrow 133). The head suspension assembly includes a suspension 135 and a head carrier such as a gas bearing slider 120, which has one end attached to the end of the actuator arm 131 and is attached to the other end of the suspension 135. The suspension 135 allows the slider 120 to remain very close to the surface of the disk 150 and enables it to "tilt" and "roll" on a gas (typically air or helium) bearing generated by the disk as the disk 150 rotates in the direction of arrow 20. The slider 120 supports a HAMR head (not shown) that includes a magnetoresistive read head, an inductive write head, a near field transducer (NFT), and an optical waveguide. A semiconductor laser 88 having a wavelength of 780 nm to 980 nm may be used as a HAMR light source and is depicted as being supported on top of a slider 120. Alternatively, the laser may be located on a suspension 135 and coupled to the slider 120 through an optical channel. Movement of the actuator 130 allows the HAMR head on the slider 120 to access different data tracks 118 on the disk 150 as the disk 150 rotates in the direction of arrow 20. The slider 120 is typically formed of a composite material, such as a composite material of aluminum oxide / titanium carbide (Al2O3 / TiC). Figure 1 Only one disk surface with an associated slider and read / write head is shown in FIG, but typically multiple disks are stacked on a hub rotated by a spindle motor, with a separate slider and HAMR head associated with each surface of each disk.

[0022] In the following drawings, the X-axis represents the axis perpendicular to the gas bearing surface (GBS) of the slider, the Y-axis represents the track width or the cross-track axis, and the Z-axis represents the along-track axis. Figure 2 is a schematic cross-sectional view showing a configuration example of a HAMR head according to the prior art. Figure 2 , a disk 150 is depicted as having a recording layer 31, which is a conventional continuous magnetic recording layer of a magnetizable material having magnetized regions or "bits" 34. A gas bearing slider 120 is supported by a suspension 135 and has a GBS facing the disk 150 and supporting a magnetic write head 50, a read head 60, and magnetically permeable read head shields S1 and S2. The recording magnetic field is generated by the write head 50, which is composed of a coil 56, a primary pole 53 for transmitting the flux generated by the coil 56, a main pole 52 connected to the primary pole 53, and a return pole 54 coupled to the primary pole 53 and the main pole 52. The magnetic field generated by the coil 56 is transmitted through the primary pole 53 to the main pole 52 disposed near an optical near field transducer (NFT) 74. Figure 2A write head 50 is shown with a known "flat" coil 56, wherein the coil segments lie in substantially the same plane. Alternatively, however, the coil may be a known "spiral" coil, wherein the coil is wound around a primary magnetic pole 53. At the moment of recording, the recording layer 31 of the disk 150 is heated by the optical near field generated by the NFT 74, and at the same time, the area or "bit" 34 is magnetized and thus written to the recording layer 31 by applying a recording magnetic field generated by the main pole 52.

[0023] The semiconductor laser 88 is mounted to the top surface of the slider 120. An optical waveguide 73 for guiding light from the laser 88 to the NFT 74 is formed in the slider 120. A material that ensures that the refractive index of the core material of the waveguide 73 is greater than the refractive index of the surrounding cladding material (not shown) can be used for the waveguide 73. For example, Al2O3 can be used as the cladding material, and TiO2, T2O5, and SiO x N y Alternatively, SiO2 can be used as a cladding material, and Ta2O5, TiO2, Nb2O5, SiO x N y Or Ge-doped SiO2 is used as the core material. The waveguide 73 that transmits light to the NFT 74 is preferably a single-mode waveguide.

[0024] Figure 3A1 is a side cross-sectional view of a prior art HAMR head and shows the material layers that make up the primary magnetic pole 53, the main pole 52, the NFT 74 and the waveguide 73, and is shown relative to the disk 150 with the recording layer 31. The main pole 52 is typically a layer of high magnetic moment material such as FeCo, and has a pole tip 52a at the GBS. The waveguide 73 is a core material layer generally parallel to the main pole 52 layer, has a length orthogonal to the GBS, and may have a tapered region 73a extending from a region 73b recessed from the GBS to a waveguide end 73d at the GBS. The waveguide 73 has a surrounding cladding material 77 and a generally flat surface 73c facing and parallel to the NFT 74 layer. The NFT 74 layer is a conductive low-loss metal (preferably Au, but also Ag, Al, Cu, Rh, Ir or alloys thereof), generally parallel to the waveguide 73 layer and the main pole 52 layer, and is located between and spaced apart from the waveguide 73 layer and the main pole 52 layer. The NFT 74 layer has a surface 74a facing the waveguide surface 73c and spaced apart from the waveguide surface. The NFT 74 layer has an output tip 80 at the GBS. When light is introduced into the waveguide 73, an evanescent wave is generated at the surface 73c and coupled to the surface plasmon excited on the surface 74a of the NFT 74. Arrow 23 shows the propagation direction of the light in the waveguide 73, and arrow 24 shows the polarization direction of the light. The surface plasmon propagates to the output tip 80. The output tip 80 has a vertex 80a facing the main pole tip 52a and a rear edge 80b facing the waveguide surface 73c. ​​At the vertex 80a, an optical near-field point is generated in the space between the output tip vertex 80a and the main pole tip 52a at the GBS. The main pole tip 52a applies a magnetic field at the light point. A heat shunt 90 of a material with high thermal conductivity such as Au, Ag or Cu may be located between the NFT 74 and the main pole 52 to allow heat to transfer from the optical point to a heat sink material located on the cross-track side of the main pole 52. Heat shunts are described in US 8619516 B1, assigned to the same assignee as the present application.

[0025] Figure 3B is a perspective view of a prior art HAMR head, and shows heat sink material 92 in contact with heat shunt 90, as well as primary pole 53, main pole 52, NFT output tip 80 and waveguide end 73d. Figure 3Cis an enlarged perspective view showing the connection of the heat shunt 90 with the NFT output tip 80 and the heat sink material 92 on the cross-track side of the main pole 52. If the heat sink material 92 includes an element that can diffuse into the magnetic material of the main pole 52, such as Au or Cu, a diffusion barrier layer 93 is located between the main pole 52 and the heat sink material 92. The material of the diffusion barrier layer 93 can be, for example, Rh, Ru, In, Co, W, Rh oxide, Ru oxide, indium oxide, or TiN, and its thickness is preferably in the range of 5nm-10nm. If the heat sink material 92 is selected from a material that is unlikely to diffuse into the main pole 52, such as Ru or Rh, the diffusion barrier layer 93 is not required.

[0026] In an embodiment of the present invention, an additional or second heat sink material is located on the cross-track side of the waveguide. The second heat sink is in contact with the NFT and the heat shunt so that heat from the NFT output tip flows through the NFT and the heat shunt to the second heat sink material. It reduces the temperature of the NFT and thus reduces the possibility of deformation of the NFT. The second heat sink is optionally connected to the first heat sink material on the cross-track side of the main pole to further reduce the temperature of the NFT. It can also reduce the temperature of the main pole, thereby reducing the possibility of oxidation of the main pole. Figure 4A is a GBS view of an embodiment of the present invention and shows a second heat sink material 102 located on the cross-track side of a waveguide 73 having an end 73d. A waveguide cladding material 77 is located between the waveguide 73 and the second heat sink material 102. The seed layer 103 may be deposited prior to forming the heat sink material 102. Figure 4AIn an embodiment of the present invention, the optional heat shunt 100 is in substantial contact with both the first heat sink material 92 adjacent to the cross-track side of the main pole 52 having the end 52a and the second heat sink material 102, which is in direct contact or through the seed layer 94, 103. The diffusion barrier layer 93' is located between the heat shunt 100 and the first heat sink material 92 and the main pole 52 having the end 52a. The second heat sink material 102 may also be in substantial contact with the first heat sink material 92 directly or through the seed layer 94. The first heat sink material 92 and the second heat sink material 102 may be formed of any material having a thermal conductivity greater than that of alumina, such as Cu, Au, Ag, Al, W, Ru, Cr, SiN, AlN, TiC, SiC, Be, Fe, FeCo, or NiFe, but it is preferred to use a material with a high thermal conductivity, such as Cu or Au. The first heat sink material 92 adjacent to the main pole 52 having the end 52a can be formed of Cr, and the second heat sink material 102 can be formed of Cu. The preferred thickness of the heat sink material 102 is between about 300nm and 1000nm, but it can be less than 300nm or greater than 1000nm. Thicker heat sinks are better used to reduce the NFT temperature. In order to electroplate the heat sink material 102, the seed layer 103 can be Ru, Au or Cu, and can be one or more layers. The thickness of the seed layer 103 is preferably in the range of 5nm to 30nm. However, the seed layer can be greater than 30nm at the GBS, such as 100nm to 500nm. For example, the thickness can be increased at the GBS to avoid exposure to the heat sink material at the GBS during the polishing process when manufacturing the head. In addition, different seed layer materials can be used at the GBS. For example, Ru can be used for the seed layer adjacent to the side of the waveguide, and Cr can be used for the seed layer near the GBS. The second heat sink material 102 is described as an additional heat sink along with the first heat sink material 92, but in some embodiments of the present invention, the heat sink material 102 will work even without the first heat sink material 92 on the main pole side. Figure 4A In FIG. 1 , the second heat sink material 102 is adjacent to the cross-track side of the waveguide 73 and the NFT 80 (which is part of the wider NFT layer 80 ′), but alternatively it may be adjacent to the cross-track side of the waveguide 73 only, and therefore is located below (in the Z direction) the NFT layer 80 ′ or the heat shunt 100 and therefore in contact with them. Figure 4A In the embodiment of FIG. 5 , the heat sink material 102 is adjacent to both the NFT output tip 80 and the waveguide end 73 d , but does not extend to the return pole 54 in the along-track Z-direction.

[0027] Figure 4Bis a GBS view of another embodiment of the present invention and shows a second heat sink material 102' located on the cross-track side of the waveguide having end 73d, but which also extends substantially into contact with the return pole 54, either directly or through the seed layer 103. The arrows indicate heat flow from the NFT output tip 80 through the optional heat shunt 100 and / or NFT layer 80' to both the first heat sink material 92 adjacent the main pole having end 52a and the second heat sink material 102' adjacent the waveguide having end 73d. Figure 4B Also shown is an optional aspect of an embodiment of the present invention in an optically reflective layer 105 adjacent to the cross-track side of the waveguide 73 having the end 73d. The layer 105 reflects light from the waveguide 73 back to the NFT output tip 80 and improves the optical efficiency. The layer 105 can be formed of a highly optically reflective material such as Au, Rh, Ir, Cu, Ru, Pd, Cr, Pt, and Ag and alloys thereof with a thickness in the range of about 10 nm to 100 nm.

[0028] Figure 4C is a view of section 4C-4C, which is Figure 4B The XY plane of FIG. 1 and shows the tapered waveguide 73 which tapers downward to a waveguide end 73 d and overlies the heat diverter 100 . Figure 4C Also shown is the cross-track gap width at the GBS between the two side reflective layers 105. By optimizing the gap width, light is more effectively confined at the apex of the NFT, so the required laser power and NFT temperature can be reduced, and the thermal gradient in the recording layer can be improved. The preferred gap width is between about 400nm and 1200nm. The optimal gap width depends on the refractive index of the waveguide core and cladding and the NFT design, as well as the corner angle θ between the reflective layer 105 and the GBS. When θ is about 70 degrees, the optimal gap width is about 600nm. The corner angle is preferably between 45 degrees and 90 degrees.

[0029] Figure 4D is with Figure 4C A similar cross-sectional view is shown, and a modification of the heat diverter 100 is shown. Figure 4A , the heat shunt 100 can be truncated at the edge of the seed layer 103 (or directly contact the heat sink material 102 if the seed layer is not formed at the edge of the heat shunt 100), so that the cross-track end is adjacent to the second heat sink material 102. Alternatively, the thickness of the seed layer 103 can be made as thin as possible, such as 10nm-20nm, so that the seed layer 103 does not block the heat flow from the NFT through the heat shunt 100 to the side heat sink material 102. Figure 4DIn the embodiment, the cross-track end of the heat shunt 100' overlaps and directly contacts the side heat sink material 102', so that the heat flow is not blocked by the seed layer 103. If it is necessary to increase the heat flow from the NFT to the side heat sink material 102', the height (X direction) of the heat shunt 100' can be increased. In some embodiments, the NFT layer 80' can also extend in the cross-track direction to overlap with the second heat sink material 102. Figure 4D It is also shown that the heat diverter 100' can be extended to have an edge at the GBS so that heat can also flow to the GBS and further reduce the NFT temperature.

[0030] Figure 4E is with Figure 4C Similar cross-sectional view, and showing an optional modification, where the side heat sink layer 102' at the GBS forms a rounded corner. The corner 104 between the seed layer 103 (and therefore the heat sink material 102') at the side of the waveguide 73 and the seed layer 103 (and therefore the heat sink material 102') at the GBS can be rounded at the GBS.

[0031] Figure 4F is with Figure 4C A similar cross-sectional view and shows a modification where the side heat sink material 102' and corresponding seed layer 103 are recessed from the GBS. This will avoid exposure of the heat sink material 102' and seed layer 103 at the GBS during polishing during head fabrication.

[0032] Figure 5 GBS view of an embodiment of the present invention showing two optional features. The first heat sink material adjacent to the main pole 52 having the end 52a may include at least two different types of heat sink materials. The heat sink layer 92a directly adjacent to the side of the main pole may be formed of Cr, and the heat sink layer 92b adjacent to the layer 92a and substantially in contact with the second heat sink material 102 may be formed of another material such as Cu. Figure 5 Also shown is an optional third heat sink material 106 that is adjacent to the return pole 54 (on the cross-track or Y-direction side of the return pole 54) and in substantial contact with the second heat sink material 102. Alternatively, the third heat sink material may be adjacent to the return pole 54 by being recessed in the X-direction from the GBS on the other side of the return pole 54. With the use of a third heat sink material adjacent to the return pole 54 (in the Y or X-direction) and a second heat sink material 102 adjacent to the waveguide 73, the head temperature may be substantially reduced without the need for a first heat sink material adjacent to the main pole.

[0033] Although the present invention has been specifically shown and described with reference to preferred embodiments, it will be appreciated by those skilled in the art that various changes may be made in form and detail without departing from the spirit and scope of the present invention. Therefore, the disclosed invention is considered to be exemplary only and is limited in scope to the scope specified in the appended claims.

Claims

1. A heat-assisted magnetic recording (HAMR) head for writing to a magnetic recording layer, the HAMR head comprising: a head carrier having an along-track axis and a cross-track axis substantially orthogonal to the along-track axis; a main pole located on a surface substantially orthogonal to the surface facing the recording layer and having an output terminal located substantially at the surface facing the recording layer; a near field transducer (NFT) layer, the NFT layer being oriented substantially parallel to the main pole and being located on the head carrier, the NFT layer having an output tip at the surface facing the recording layer, the output tip being aligned with the main pole output end in the along-track direction; an optical waveguide located on the head carrier for optical coupling with the NFT layer, the waveguide having a core, a length generally orthogonal to the recording layer facing surface and an end facing the recording layer facing surface; a heat sink material adjacent a cross-track side of the core of the waveguide; as well as An optically reflective material is adjacent each side of a cross-track side of the end of the waveguide between the end of the waveguide and the heat sink material. 2 . The HAMR head of claim 1 , further comprising a seed layer material between the core of the waveguide and the heat sink material.

3. The HAMR head of claim 1, wherein a cross-track gap width between the optically reflective material adjacent to the sides of the end of the waveguide at the recording layer-facing surface is between about 400 nm and 1200 nm.

4. The HAMR head according to claim 1, wherein the optical reflective material is selected from one or more of Au, Rh, Ir, Cu, Ru, Pd, Cr and Ag. 5 . The HAMR head of claim 1 , further comprising a waveguide cladding material located between the end of the waveguide and the heat sink material.

6. The HAMR head of claim 1, further comprising a heat shunt interconnecting the output tip of the NFT layer with the heat sink material.

7. The HAMR head of claim 6, wherein the heat shunt has a cross-track end that abuts the heat sink material.

8. The HAMR head of claim 6, wherein the heat shunt has a cross-track end that overlaps the heat sink material.

9. The HAMR head of claim 6, wherein the heat shunt has an edge substantially at the recording layer-facing surface.

10. The HAMR head of claim 1, wherein the NFT layer has a cross-track end that abuts the heat sink material.

11. The HAMR head of claim 1 , wherein the NFT layer has cross-track ends that overlap the heat sink material.

12. The HAMR head of claim 1 , further comprising a return pole located on a surface substantially orthogonal to the surface facing the recording layer, the return pole coupled to the main pole and having an end substantially located at the surface facing the recording layer; and wherein the heat sink material is substantially in contact with the return pole.

13. The HAMR head according to claim 1, further comprising a return pole located on a surface substantially orthogonal to the surface facing the recording layer, the return pole being coupled to the main pole and having an end substantially located at the surface facing the recording layer; and the HAMR head further comprising a third heat sink material adjacent to the return pole and substantially in contact with the heat sink material.

14. The HAMR head of claim 1, wherein the heat sink material at the recording layer-facing surface forms rounded corners.

15. The HAMR head of claim 1, wherein the heat sink material is recessed from the recording layer-facing surface.

16. The HAMR head of claim 1, wherein the output tip of the NFT layer has a generally triangular or trapezoidal shape.

17. The HAMR head of claim 1, wherein the waveguide has a tapered portion that tapers from a region recessed from the recording layer-facing surface to an end near the recording layer-facing surface in a cross-track width.

18. The HAMR head of claim 1, wherein the heat sink material adjacent the cross-track side of the core of the waveguide comprises a second heat sink material, and the HAMR head further comprises a first heat sink material adjacent a cross-track side of the main pole. The HAMR head of claim 18 , wherein the second heat sink material is in substantial contact with the first heat sink material.

20. The HAMR head of claim 18, wherein the first heat sink material and the second heat sink material are selected from Cu, Au, Ag, Al, W, Ru, Cr, SiN, AlN, TiC, SiC, Be, Fe, FeCo, and NiFe.

21. The HAMR head of claim 18, further comprising a diffusion barrier layer between the first heat sink material and the cross-track side of the main pole.

22. The HAMR head of claim 1, wherein the heat sink material adjacent the cross-track side of the core of the waveguide is selected from the group consisting of Cu, Au, Ag, Al, W, Ru, Cr, SiN, AlN, TiC, SiC, Be, Fe, FeCo, and NiFe.

23. A heat-assisted magnetic recording (HAMR) disk drive, the HAMR disk drive include: The HAMR head of claim 1, further comprising a magnetoresistive read head on the head carrier; a laser for directing light into the waveguide; and A magnetic recording disk having a magnetic recording layer.

24. A heat-assisted magnetic recording (HAMR) head for writing to a magnetic recording layer on a magnetic recording disk, the HAMR head comprising: a gas bearing slider having a gas bearing surface (GBS) for facing the magnetic recording layer on the disk, the GBS having a along-track axis and a cross-track axis orthogonal to the along-track axis; a main pole located on a surface substantially normal to the GBS and having an output terminal located substantially at the GBS; a first heat sink material adjacent to a cross-track side of the main pole; a near field transducer (NFT) oriented substantially parallel to the main pole and located on the slider, the NFT having an output tip at the GBS, the output tip being aligned with a main pole output end in a down-track direction; an optical waveguide on the slider for optical coupling with the NFT, the waveguide having a length generally orthogonal to the GBS and a tapered portion that tapers across the track width from a region recessed from the GBS to an end near the GBS; a waveguide cladding material adjacent a cross-track side of the tapered portion of the waveguide; a second heat sink material adjacent to a cross-track side of the waveguide cladding material; a thermal shunt interconnecting the output tip of the NFT with the first heat sink material and the second heat sink material; as well as An optically reflective material is provided between the waveguide cladding material and the second heat sink material.

25. The HAMR head of claim 24, further comprising a seed layer material between the waveguide cladding material and the second heat sink material.

26. The HAMR head of claim 24, wherein the second heat sink material is in substantial contact with the first heat sink material.

27. The HAMR head of claim 24, further comprising a return pole located on a surface substantially orthogonal to the GBS, the return pole coupled to the main pole and having an end substantially located at the GBS; and wherein the second heat sink material is substantially in contact with the return pole.

28. A heat-assisted magnetic recording (HAMR) disk drive, the HAMR disk drive comprising: The HAMR head according to claim 27; a magnetoresistive read head located on the slider; a laser for directing light into the waveguide; and A magnetic recording disk having a magnetic recording layer.

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