Влияние кристаллической структуры подложки на магнитную анизотропию плeнок Mn-=SUB=-x-=/SUB=-Si-=SUB=-1-x-=/SUB=- (x~0.5)

Abstract

Thin films of MnxSi1-x (x ≈ 0.5) alloy were synthesized by pulsed laser deposition in a droplet-free mode on sapphire substrates with different crystallographic orientations of the cut plane (c-Al2O3 and r-Al2O3) at various laser energy densities E at the polycrystalline MnSi target. The X-ray structural, as well as static and resonance magnetic properties of the films were studied depending on E and the orientation of the substrate. The films deposited at high E > 6 J/cm2 are found to demonstrate the presence of a ferromagnetic phase with anomalously high Curie temperature TC ~ 300 K which is not typical of MnSi single crystals (TC ≈ 30 K). In the case of the c-Al2O3 sub-strates, the magnetic moment of the films turns out to be somewhat higher than in the case of the r-Al2O3 substrates. Moreover, the films deposited on the c-Al2O3 substrates exhibit noticeably higher values of the effective surface anisotropy field 4πMeff measured by ferromagnetic resonance. The data obtained indicate a significant effect of the substrate structure on the formation and magnetic properties of the high-temperature ferromagnetic phase in the MnxSi1-x films.