Power Absorption and Thermal Analysis of Head and Media for Heat-Assisted Magnetic Recording

A method from near-field optics to thermal analysis is developed for the heat-assisted magnetic recording (HAMR) head and media. The distributions of power absorptions in the system of the HAMR head and media are simulated with finite-difference time-domain (FDTD), which is coupled with transiently thermal conduction equation for thermal analysis. The study focuses on the influence of the writer pole on the efficiency of transducer and thermal performance of the HAMR head and media. The results show that the efficiency of transducer largely reduces from 3.36% to 0.55% due to the power absorption of the writer poles. However, the writer pole plays a role of thermal sink bar so that the temperature of transducer also reduces largely. The distance between the transducer and writer pole strongly affects the efficiency of transducer, temperatures of media, transducer and writer pole. It is found that without the thermal sink role of the writer pole, the temperature of transducer is very high when the media temperature is required to reach the Curie temperature of FePt media. Two shapes of the writer poles including rectangle and step-down shapes have been used for the efficiency and thermal analysis. Their size effects on efficiency and temperatures are also studied.