The utilization of boron nitride (BN) for granular L1-FePt HAMR media fabrication

In this experimental study, we present a dual-layer structure of FePt-boron nitride (BN)/FePt-SiOx granular media for the heat-assisted magnetic recording. The boron nitride (BN) was deposited together with FePt at 700 °C for the first 2.5 nm in the initial film growth. After the initial growth, SiOx was used to replace the BN to serve as the grain boundary material for the rest of film growth process. The transmission electron microscopy study on the fully grown FePt-BN/FePt-SiOx film shows well-isolated FePt grains that are fully encircled by the well-defined grain boundaries. The areal density of FePt grains is distinctively higher than that of the conventional granular FePt-C-based film at similar film thickness. The FePt-BN/FePt-SiOx bilayer granular media also demonstrate excellent magnetic properties, which are comparable to that of FePt-C-SiOx granular media in terms of the hysteresis characteristics.