Comparison between the in-plane anisotropies and magnetostriction constants of thin epitaxial Fe films grown on GaAs and Ga0.8In0.2As substrates, with Cr overlayers

Abstract

Thin epitaxial Fe films grown on GaAs(100) and Ga0.8In0.2As(100) substrates were investigated to determine how tuning the lattice constant mismatch between the Fe and the substrate may change the in-plane anisotropies and the magnetostriction. Two sets of Fe films were grown using molecular-beam epitaxy, each capped with a Cr overlayer. For each film, the in-plane anisotropy constants were determined from the normalized magnetization loops measured using a magneto-optic Kerr effect magnetometer. The lattice mismatch was found to give no contribution to the in-plane anisotropies. For all the films the magnetostriction constants, determined by the Villari method, were negative and became more negative as the Fe thickness decreased.