Room-Temperature Study of the Magnetic Moment of Ultrathin Fe Films on GaAs

We present magnetometry data for a range of Fe thicknesses grown on GaAs and InAs substrates in order to determine the factors governing the evolution of the magnetic moment of epitaxial Fe grown on a zinc-blende semiconductor. Fe films grown at room temperature by molecular beam epitaxy were characterized structurally and magnetically. The estimated roughness amplitudes were 0.3plusmn0.2 nm for the Fe/GaAs interface and 0.6plusmn0.2 nm for Fe/InAs. We observe a greater reduction of the Fe magnetic moment for films grown on InAs as compared to GaAs, as the Fe films reach a bulk-like moment (within 10% deviation) at a thickness of ~5.2 nm and ~2.2 nm, respectively. We conclude that the growth conditions, in particular interface and interdiffusion effects, are the dominant mechanisms influencing the value of the magnetic moment for ultrathin Fe films on GaAs and InAs