Investigation of near-field heat transfer of multilayered structures in heat-assisted magnetic recording (HAMR)

Heat-assisted magnetic recording (HAMR) is a promising method to increase the area density to 1 Tb/in2 in hard disk drives. In HAMR, a pulsed laser is used to heat the magnetic medium above its Curie temperature. High temperatures can cause lubricant depletion, degradation, and carbon overcoat damage at the head disk interface. Near-field radiation effects in HAMR are important to contribute the heat transfer and hence the flying ability at the head disk interface. Therefore investigation of the near-field heat transfer is essential to optimize the head disk interface. An equivalent simulation model of the head disk interface for studying the radiative heat transfer is provided in this paper. The head can be simplified as a nanosphere, while the disk can be simplified to a semi-infinite multilayer structure, the thickness of every layer in the multilayer structure is nano-scale. And the distance between head and disk is smaller than 10nm. The near field heat transfer problem can be solved by combining the dyadic Green's functions with the fluctuations electrodynamics, and the scattering matrix approach is used in the multilayer structure. Considering both the nonmagnetic media and the magnetic media, several numerical computations are conducted.