Influence of substrate crystal structure on the magnetic anisotropy of Mn$_{x}$Si$_{1-x}$ ($x\approx0.5$) films

Thin films of Mn$_{x}$Si$_{1-x}$ ($x\approx0.5$) alloy were synthesized by pulsed laser deposition in a droplet-free mode on sapphire substrates with different crystallographic cut-off plane orientations ($c$-Al$_{2}$O$_{3}$ and $r$-Al$_{2}$O$_{3}$) at various laser energy densities $E$ at the polycrystalline target MnSi. X-ray structure properties, as well as static and resonance magnetic characteristics of the films depending on the value of $E$ and substrate orientation were investigated. The presence of a ferromagnetic phase with an unusually high Curie temperature $T_{C}\sim$ 300 K which is untypical of MnSi single crystals ($T_{C}\approx$ 30 K) was revealed in films deposited using high laser energy densities $E>6$ J/cm$^2$ at the target. The magnetic moment of the films on $c$-Al$_{2}$O$_{3}$ substrates is somewhat larger than in the case of $r$-Al$_{2}$O$_{3}$ substrates. Moreover, the films deposited on $c$-Al$_{2}$O$_{3}$ substrates show significantly higher values of the effective magnetic anisotropy field $4\pi M_{\operatorname{eff}}$, measured by ferromagnetic resonance. Obtained data show that the structure of the substrate has a remarkable influence on the formation process and magnetic properties of the high-temperature ferromagnetic phase in the Mn$_{x}$Si$_{1-x}$ films.