Fabrication of 16 nm Thick Granular L10 FePt-hBN Thin Film Media

Hexagonal boron nitride ( ${h}$ BN) has recently been investigated as a promising grain boundary material (GBM) for the nanogranular structure of L10-FePt-based heat-assisted magnetic recording (HAMR) media. In this study, we systematically investigated FePt- ${h}$ BN granular thin films (7.5 nm) with various ${h}$ BN concentrations to provide a fundamental understanding of the effect of introducing ${h}$ BN nanosheets in the medium film on its microstructure and magnetic properties. Following the optimization of the ${h}$ BN concentrations, we demonstrated a method to fabricate a thicker recording layer while maintaining the desired nanogranular microstructure. We successfully fabricated the 16 nm thick FePt- ${h}$ BN film with well-isolated columnar grains of diameter 6.4 nm, grain aspect ratio 2.5, and decent magnetic properties ( ${H} _{\mathbf {C\bot }}$ = 21.3 kOe and ${H} _{\mathbf {C//}}$ = 5 kOe).