Thermal effect of a thin overcoating layer subject to laser heating

This paper concerns the effect of a thin overcoating layer on the temperature increase in heat-assisted magnetic recording disk structure induced by laser heating. The optical absorption model, which derived from Maxwell's equation, is applied to quantify local energy absorption by the media. The numerical simulations indicate that the presence of a 2-nm overcoating layer results in additional 5% temperature increase in the disk, compared with that without overcoating layer. The temperature gradient between the overcoating layer and its neighbor layer is negligible small. The present study indicates that besides its mechanical properties, the thermal and optical properties of the overcoating material are important design factors.