Magnetism and interface properties of epitaxial Fe films on high-mobility GaAs/Al_0.35Ga_0.65As(001) two-dimensional electron gas heterostructures

An optimized heterostructure design and an optimized surface sputter-cleaning procedure allow thegrowth of high-quality epitaxial Fe(001) thin films at Ts 50 ° C on selectively doped GaAs/Al0.35Ga0.65 As heterostructures, while retaining the high quality transport property of thetwo-dimensional electron gas. Magneto-optic Kerr effect measurements and model calculationsindicate a dominant uniaxial in-plane anisotropy (easy axis along [110], hard axis along [1-10] and small coercivity (~15 Oe). Interface sensitive 57Fe Mössbauer measurements prove the absenceof both magnetic ‘‘dead layers’’ and ‘‘half-magnetization’’ phases (compared to pure Fe), and provide evidence for intermixing within a few monolayers, retaining, however, a metallic Fe stateand high Fe magnetic moments at the interface