Plasmon generator with metallic waveguide blocker for TAMR

• US 9,852,752 B1
• Filed: 08/12/2016
• Issued: 12/26/2017
• Est. Priority Date: 08/12/2016
• Status: Active Grant

• Current Assignee: Headway Technologies Incorporated
• Original Assignee: Headway Technologies Incorporated
• Inventors: Chou, Tsutomu, Shimazawa, Kouji, Maletzky, Tobias, Xu, Weihao, Hara, Shinji, Tsuchiya, Yoshihiro, Wang, Yiming, Han, Cherng-Chyi, Jin, Xuhui
• Primary Examiner(s): Dinh, Tan X
• Application Number:
  US15/235,171
• Time in Patent Office: 501 Days
• Field of Search: None
• CPC Class Codes: G11B 11/10506 by modulating only the light beam of the transducer
• CPC Class Codes: G11B 11/1051 by modulating both the magnetic field and the light beam at the transducers
• CPC Class Codes: G11B 2005/0021 Thermally assisted recording using an auxiliary energy source for heating the recording layer locally to assist the magnetization reversal
• CPC Class Codes: G11B 5/1278 specially adapted for magnetisations perpendicular to the surface of the record carrier
• CPC Class Codes: G11B 5/3106 where the integrated or assembled structure comprises means for conditioning against physical detrimental influence, e.g. wear, contamination G11B5/3133 takes precedence
• CPC Class Codes: G11B 5/3136 for reducing the pole-tip-protrusion at the head transducing surface, e.g. caused by thermal expansion of dissimilar materials
• CPC Class Codes: G11B 5/314 where the layers are extra layers normally not provided in the transducing structure, e.g. optical layers G11B5/3196 takes precedence
• CPC Class Codes: G11B 5/3163 Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers
• CPC Class Codes: G11B 5/4866 the arm comprising an optical waveguide, e.g. for thermally-assisted recording
• CPC Class Codes: G11B 5/6082 Design of the air bearing surface
• CPC Class Codes: G11B 5/6088 Optical waveguide in or on flying head

Abstract

A TAMR (thermal assisted magnetic recording) write head has a metal blocker formed against a distal end of a waveguide. The waveguide focuses optical radiation on an adjacent plasmon generator where it excites plasmon modes that heat the recording medium. Although the plasmon generator typically heats the recording medium using the plasmon near field to supply the required Joule heating, an unblocked waveguide would also send optical radiation to the medium and surrounding structures producing unwanted heating and device unreliability. The role of the blocker is to block the unwanted optical radiation and, thereby, to limit the heating to that supplied by the plasmon near field.

Claims

1. A TAMR (thermally assisted magnetic recording) write head comprising:

an induction type magnetic writer having a main write pole emerging at a distal ABS (air-bearing surface);

a waveguide, having a dielectric core, formed adjacent to said main write pole for directing electromagnetic radiation at a plasmon generator;

said plasmon generator formed alongside and adjacent to said waveguide and beneath said main pole and said plasmon generator being electromagnetically coupled to said waveguide at a distal end of said waveguide, whereby plasmon modes are excited within said plasmon generator due to mode beating, said modes having near-field energy that is directed at a confined region of a recording medium immediately adjacent to said ABS of said main write pole within which confined region said near fields produce Joule heating;

a scalable, bottom tapered metallic peg emerging distally from said plasmon generator for further concentrating said near-field plasmon energy at said confined region of said recording medium;

a waveguide blocker formed on a heat sink layer and abutting against said distal end of said waveguide and configured to prevent radiative energy emitted from a distal end of said waveguide from being transferred to said confined region of said recording medium and its surroundings;

wherein

said waveguide blocker is of triangular cross-section, having a horizontal base that physically and thermally contacts said heat sink layer and wherein said waveguide blocker has a planar tapered side that is formed at a blocker angle, BWA, to said horizontal base, wherein said planar tapered side is adjacent to and conformal with a similarly tapered side formed on said distal end of said waveguide and separated from said distal end by a dielectric filled uniform gap said dielectric having a smaller refractive index than a dielectric index of said waveguide core.

2. The TAMR write head of claim 1 wherein said waveguide blocker is formed of a metal, which is electrically conducting but may be magnetic or non-magnetic.

3. The TAMR write head of claim 2 wherein said non-magnetic metal is Ru, Ta, Rh or Cr or any of their alloys or combinations.

4. The TAMR write head of claim 2 wherein said magnetic metal is Fe, Co or Ni or any of their alloys or combinations.

5. The TAMR write head of claim 1 wherein dimensions of said blocker are:

BWR (vertical height of the dielectric spacer where it emerges at the ABS) is approximately equal to 100 nm, BWB (space between blocker face and waveguide face) is approximately equal to 140 nm and said blocker angle BWA is approximately equal to 45°

.

6. The TAMR write head of claim 1 wherein said dielectric material filling said gap is SiO₂ or alumina and said waveguide core is TaOx.

7. The TAMR write head of claim 1 wherein said plasmon generator has a flat parabolic horizontal cross-sectional shape and is aligned symmetrically with said waveguide.

8. The TAMR write head of claim 7 wherein said plasmon generator may be aligned above or below said waveguide.

9. The TAMR write head of claim 1 wherein said peg has the following dimensions:

lPeg (length of peg) between approximately 10 nm to 40 nm, hPeg (height of peg) between approximately 70 nm and 100 nm, wPeg (width of peg) between approximately 30 nm and 70 nm.

10. The TAMR write head of claim 1 wherein said bottom tapered peg has an upward sloping bottom taper of between 30°

and 60°

.

11. The TAMR write head of claim 1 wherein said peg has a height in the ABS plane, hPegA, of between approximately 40 nm and 60 nm.

12. The TAMR write head of claim 1 wherein said heat sink layer is a leading edge shield.