Temperature distribution of granular media for heat assisted magnetic recording

The thermal distribution of granular media for heat assisted magnetic recording has been explored by the heat Fourier equation; particularly, the effect of the thermal conductivities in the grain boundary has been extensively investigated. When the thermal conductivity is sufficiently small, the grain boundary provides a natural constraint to heat dissipation: the effective in-plane thermal conductivity can be ten times smaller than that of FePt with the decrease limited only by the heat dissipation through the interlayer MgO. For low thermal conductivities in the grain boundary, the out of plane thermal gradient increases sharply owing to the inability of the heat to spread. Therefore, a compromise between power consumption and uniformity of the temperature distribution within grains should be taken into account when optimizing the media design.