Microstructure evolution in FePt-Cr2O3 granular thin films.

• FePt-Cr 2 O 3 granular film shows the highest grain density of 25.2 Tgrain/in2 in FePt-based granular film. • Low L 1 0 order is due to a small contact area at the MgO/FePt-Cr 2 O 3 interface and Cr diffusion. • The solid–liquid interfacial energy in the FePt granular system was a key factor in controlling the microstructures. Increase in the FePt grain density is necessary to achieve an ultra-high recording density of the heat-assisted magnetic recording. Herein, the highest grain density in FePt-Cr 2 O 3 granular thin films was obtained by utilizing a densified FePt nucleation layer. The reduced magnetic properties were attributed to the grain shape and effect of elemental diffusion at the FePt/Cr 2 O 3 interface. The equilibrium shape of the FePt grains indicated that the solid–liquid interfacial energy in the FePt granular system is a key factor in controlling the microstructures. [ABSTRACT FROM AUTHOR]