Influence of Au capping layer on the magnetic properties of Fe/GaAs(0 0 1) ultrathin films

The effect of an Au covering layer on the magnetic anisotropy of ultrathin Fe/GaAs(0 0 1) films has been studied in situ by Brillouin light scattering, i.e. inelastic scattering of photons by thermal spin waves. It has been found that the presence of an Au overlayer determines a dramatic reduction of the in-plane uniaxial anisotropy. In particular, for films thickness up to 7 monolayers (ML) the uniaxial anisotropy is completely suppressed, while it is reduced to a half for a thickness as large as 20 ML. A qualitative interpretation of these experimental data has been achieved by a fully relativistic approach using the tight-binding Korringa–Kohn–Rostoker method of band structure calculation.