SATURATION MAGNETIZATION AND PERPENDICULAR ANISOTROPY OF FE/GAAS(110) EPITAXIAL-FILMS STUDIED BY THE EXTRAORDINARY HALL-EFFECT

The magnetic field dependence of the extraordinary Hall effect (EHE) has been used to determine the sum of the perpendicular magnetic anisotropy and the saturation magnetization of thin (5-20 nm) Fe films. The films were grown on (110) surfaces of GaAs by molecular beam epitaxy. The relation between the film thickness and the sum of the perpendicular anisotropy energy and the saturation magnetization was compared to that determined in a previous study which relied on ferromagnetic resonance (FMR) to measure the same quantity. The FMR study measured both oxide covered films and also films with a protective overcoating of Al to prevent oxidation. It is found that the data from the EHE are not in agreement with the FMR data taken on the iron oxide covered films but instead are in agreement with the FMR data of the protected or nonoxidized films.