Heat-assisted magnetic recording head with a near-field transducer extending beyond the media-facing surface
A recording head has a waveguide that delivers optical energy from an energy source and a write pole extending to a media-facing surface of the recording head. The recording head also has a near-field transducer coupled to receive the optical energy from the waveguide and emit surface plasmons from the media-facing surface towards a recording medium while the write pole applies a magnetic field to the recording medium. The near-field transducer has an extended portion that, as-manufactured, protrudes beyond the media-facing surface by a first distance.
1. A recording head, comprising:
a waveguide that delivers optical energy from an energy source;
a write pole extending to a media-facing surface of the recording head; and
a near-field transducer coupled to receive the optical energy from the waveguide and emit surface plasmons from the media-facing surface towards a recording medium while the write pole applies a magnetic field to the recording medium, the near-field transducer comprising a plasmon resonating part that, as-manufactured, protrudes beyond the media-facing surface by a first distance.
2. The recording head of claim 1 , wherein the plasmon resonating part of the near-field transducer comprises Ir or Rh.
3. The recording head of claim 1 , wherein a region of material surrounding the plasmon resonating part of the near-field transducer extends from the media-facing surface by the first distance to form a pedestal.
4. The recording head of claim 3 , wherein the pedestal does not exceed 2 μm in size in a downtrack direction.
5. The recording head of claim 4 , wherein the pedestal does not exceed 1 μm in size in a downtrack direction.
6. The recording head of claim 3 , further comprising a contact detection sensor that is located downtrack from the pedestal, wherein the pedestal is separated from the contact detection sensor by at least 0.5 μm.
7. The recording head of claim 1 , wherein the first distance is between 2 and 6 nm.
8. The recording head of claim 1 , further comprising a carbon overcoat over the media-facing surface, the carbon overcoat covering at least part of the plasmon resonating part that protrudes beyond the media-facing surface.
9. The recording head of claim 1 , further comprising a contact detection sensor at the media-facing surface, wherein the extended portion of the near-field transducer is separated from the contact detection such that the contact detection sensor detects contact between the plasmon resonating part and a recording medium.
10. The recording head of claim 1 , further comprising a contact detection sensor at the media-facing surface, wherein the extended portion of the near-field transducer is separated from the contact detection sensor such that the contact detection sensor detects contact between a recording medium and a region of the media-facing surface located away from the plasmon resonating part.
11. A method, comprising:
measuring a signal from a contact detection sensor that is at a media-facing surface of a recording head, the recording head comprising a near-field transducer that creates a hotspot on a recording medium while a magnetic field is applied to the hotspot, the near-field transducer comprising an extended portion that, as-manufactured, protrudes beyond the media-facing surface by a first distance;
based on a transition in the signal, determining contact between the recording head the recording medium; and
based on the determination of the contact, applying a control signal to a clearance actuator of the recording head, the control signal causing the media-facing surface to maintain a first head-to-media spacing from the recording medium, the control signal causing the extended portion of the near-field transducer to maintain a second head-to-media spacing from the recording medium that is less than the first head-to-media spacing.
12. The method of claim 11 , wherein the contact is between the recording head and a region of the media-facing surface located away from the extended portion of the near-field transducer, and wherein a response of the control signal is based on maintaining the first head-to-media spacing.
13. The method of claim 11 , wherein the contact is between the recording head and the extended portion of the near-field transducer, and wherein a response of the control signal is based on maintaining the second head-to-media spacing.
14. The method of claim 11 , further comprising, determining that the near-field transducer will be idled, and in response thereto, performing a dummy write to coat the extended portion with an oxide to reduce corrosion.
15. The method of claim 14 , wherein the dummy write is performed at a head-to-media separation that is high enough to prevent data from being written to the recording medium.
16. The method of claim 14 , wherein the dummy write is performed at a part the recording medium where no important data is stored.
17. The recording head of claim 1 , wherein the surface plasmon resonating part comprises a peg extending from an enlarged part of the near-field transducer.
18. The recording head of claim 17 , wherein the enlarged part comprises an Au disc.