Influence of Au capping layer on the magnetic properties of ultrathin epitaxial Fe3O4/GaAs(001) film

The effect of the Au capping layer on the magnetic anisotropies and molecular magnetic moment of ultrathin epitaxial Fe3O4 films on GaAs(100) substrate was studied by MO Kerr effect, superconducting quantum interference device, and Ferromagnetic resonance, respectively. The films with and without capping layers show a predominant in-plane uniaxial magnetic anisotropy and a minor fourfold anisotropy. The Au capping layer was found to increase significantly the uniaxial magnetic anisotropy related to the magnetoelastic interactions at the Au/Fe3O4 interface, and unexpectedly reduce saturation molecular magnetization due to the interfacial diffusion between Au layer and Fe3O4 layer.