L1₀ FePt Films with Optimal (001) Texture on Amorphous SiO₂/Si Substrates for High-Density Perpendicular Magnetic Recording Media

Highly ordered L1 0 FePt films with the highest degree of [001] preferred orientation were prepared by multilayer deposition on amorphous oxidized Si substrates and subsequent rapid thermal annealing (RTA). We identify how to synthesize the preferred orientation structure on the amorphous substrate, which we find to be critical to the optimal formation of the [001] preferred orientation. This was achieved by controlling the heating rate of the RTA process. We also identify how the influence of the beam power, sputtering working pressure, and annealing time affect the structural and magnetic properties of FePt films. For example, a L1 0 preferred orientation and increased magnetic anisotropy of the FePt films have been attained by composition and in-plane tensile stress adjustments. The perpendicular field coercivity was enhanced by increasing the RTA heating rate, which increased the dislocation densities induced by strain. We also found that the strain fields of dislocations in FePt L1 0 films can act as the dominant pinning sites that restrict domain wall motion, increasing the coercivity. We find that this is due to the spatial range of the strain fields associated with dislocations being similar to the domain wall width in the films.