A comparative analysis of Ag and Cu heat sink layers in L1_0-FePt films for heat-assisted magnetic recording

摘要

The magnetic properties, structural properties, and thermal conductivity of FePt films deposited on Ag and Cu heat sink layers designed for use in heat-assisted magnetic recording (HAMR) were investigated. It has been found that FePt films grown on Cu have a well-defined L1_0-FePt (001) texture while the FePt films grown on Ag appear to be more isotropic. As the thickness of the heat sink layer increases from 15 to 120 nm the coercivity of the FePt films decreases from 1.7 to 1.5 T for Cu and from 1.3 to 1.0 T for Ag. The thermal conductivity measurements, carried out with the "laser-flash" technique, revealed that the overall thermal resistance of the examined structures is dominated by the thermal boundary resistance and the interface effects. The increase in the thickness of Ag and Cu heat sink layers does not lead to the higher effective thermal conductivity of the layered structure in the cross-plane direction. The obtained results are important for optimization of the FePt-based structures for HAMR.