Magnetic properties of single-crystal Fe films grown on ZnSe epilayers by molecular-beam epitaxy

Abstract

We report the magnetic properties of single-crystal α-Fe films grown by molecular-beam epitaxy (MBE) on both (110) and (001)ZnSe epilayers. These ZnSe layers were grown by MBE on GaAs substrates with (110) or (001) surfaces and a final ZnSe layer protected the Fe from oxidation. The samples were characterized by vibrating sample magnetometry and in-plane FMR in addition to x-ray fluorescence and the usual in situ surface analysis tools. Film thicknesses ranged from 140 to 3100 Å. The coercive forces are significantly smaller for these films than for similar films grown directly on GaAs substrates and the FMR linewidths indicate much smaller microwave losses. Except for the thinnest film studied, the 4πM and K1 (cubic anisotropy) values are similar to bulk Fe. The origin of the uniaxial in-plane anisotropy found in thicker (110)Fe/ZnSe and (110)Fe/GaAs films is attributed to the combination of magnetostriction and lattice mismatch-induced strain originating at the Fe/substrate interface.