Thermal deformation of thermally assisted magnetic recording head in binary gas mixture at various temperatures

Helium-filled drives and thermally assisted magnetic recording (TAMR) systems are the most promising next-generation magnetic recording technologies. Currently, a fused TAMR system under helium-or air-helium-filled conditions is expected. In the fused system, it is important to accurately predict thermal deformation for a full TAMR head model and change of flying height (FH) at near filed transducer (NFT). In this paper, we first constructed an iterative coupled-field analysis process and a more realistic TAMR head model, including the NFT and even the epoxy components. The heat transfer coefficient was calculated using derived gas mixture properties. And the thermal deformation and protrusion of TAMR head was investigated for various temperature and helium fraction ratios. From the simulation results, the maximum temperature at the laser diode (LD decreased up to 20% due to changes in the heat transfer coefficient and environmental temperature. The epoxy effect induced by the LD heating was around 40%, which is in no way negligible. A thermal protrusion of 1.0-1.5 nm occurred at the NFT at various conditions. After considering the thermal deformation of the epoxy and the protrusion at the NFT, we found that the total FH was reduced with increasing helium fraction ratio and temperature.