In this paper, we present an experimental study of L10-FePt granular films with crystalline/amorphous boron nitride (BN) grain boundary materials for heat assisted magnetic recording (HAMR). It is found that an adequate RF substrate bias yields the formation of hexagonal boron nitride (h-BN) nanosheets in grain boundaries, facilitating the columnar growth of FePt grains during sputtering at high temperatures. The h-BN monolayers conform to the side surfaces of columnar FePt grains, completely encircling individual FePt grains. The resulting core-shell FePt/h-BN nanostructures appear to be highly promising for HAMR application. The high thermal stability of h-BN grain boundaries allows the deposition temperature to be as high as 800oC such that high order parameters of FePt L10 phase have been obtained. For the fabricated FePt/h-BN thin film, excellent granular microstructure with FePt grains of 6.5nm in diameter and 11.5nm in height has been achieved along with good magnetic hysteresis properties.
@article{arxiv.2303.11411,
title = {Bias sputtering of granular $\text{L1}_0$-FePt films with hexagonal boron nitride grain boundaries},
author = {Chengchao Xu and B. S. D. Ch. S Varaprasad and David E. Laughlin and Jian-Gang and Zhu},
journal= {arXiv preprint arXiv:2303.11411},
year = {2023}
}