Sabic Global Technolgoies B.v.

Hgst Netherlands, B.v.

Gregory John Parker

Allen Lawrence Garner

Gary Stephen Balch

Davide Louis Simone

David Alexander Gibson, Iii

Harold Jay Patchen

Erhard Theodor Schreck

Barry C Stipe

Hal Jervis Rosen

Michael Grobis

Bruce David Terris

Daniel Qi Tan

Hans Juergen Richter

Francis Johnson

Richard Michael Brockie

Virat Vasav Mehta

A heat-assisted magnetic recording (HAMR) disk has multiple independent data layers, each data layer being a continuous non-patterned layer of magnetizable material. Each data layer can store data independent and not related to the data stored in the other data layers. The data layers are separated by a nonmagnetic spacer layer (SL) and each data layer is formed of high-anisotropy (K) material so that the coercivities of lower and upper data layers (RL1 and RL2) are greater than the magnetic write field. At a high laser power both RL1 and RL2 are heated to above their respective Curie temperatures and data is recorded in both RL1 and RL2. At low laser power only upper RL2 is heated to above its Curie temperature and data is recorded only in RL2. The SL prevents lower RL1 from being heated to above its Curie temperature at low laser power.

Heat-assisted magnetic recording (HAMR) disk with multiple continuous magnetic recording layers

A composition for destructive interference in at least a portion of the frequency range from about 1 GHz to about 20 GHz can comprise a dielectric and a conductive filler mixed with at least a portion of the dielectric, wherein the percentage volume of the conductive filler relative to the total volume of the composition is configured such that the wavelength of sensitivity for the composition is on the order of a wavelength of an incident electromagnetic radiation in at least a portion of the frequency range from about 1 GHz to about 20 GHz.

Methods and compositions for destructive interference

A composition for energy dissipation in at least a portion of the frequency range from about 1 GHz to about 20 GHz, the composition can comprise a dielectric and graphene mixed with at least a portion of the dielectric, wherein the percentage volume of the graphene relative to the total volume of the composition is configured such that dissipation of incident electromagnetic radiation is substantially optimized in at least a portion of the frequency range from about 1 GHz to about 20 GHz.

Methods and compositions for energy dissipation

A thermally-assisted recording (TAR) disk drive operates by turning on write current prior to the application of heat to the recording layer by the near-field transducer (NFT). In a TAR disk drive that uses thermal fly-height control (TFC), TFC power is at a first power level that keeps the write pole at a predetermined fly-height. The write current is then turned on, either simultaneously with or after a reduction in TFC power. The write pole then reaches its optimal fly-height as a result of the combination of write pole protrusion caused by the write current and retraction of the write pole caused by the reduction in TFC power. After the write pole has reached its optimal fly-height, heat is applied to the recording layer by the NFT. The combination of write current and heat causes writing to occur at the optimal write pole fly-height.

Method for controlling writing in a thermally-assisted recording (TAR) disk drive with thermal fly-height control

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San Jose, CA, United States of America

Gregory John Parker