Epitaxial growth and electrical spin injection from Fe(1-x)Gax (001) films on AlGaAs/GaAs (001) heterostructures

The authors have grown epitaxial films of Fe(1-x)Gax (0 < x < 0.75), a material noted for its high magnetostriction, on AlGaAs/GaAs (001) heterostructures and summarize the structure, magnetization, spin polarization, and results for electrical spin injection into AlGaAs/GaAs. The out-of-plane saturation field and magnetization decrease rapidly with Ga content, but the spin polarization determined by point contact Andreev reflection remains near that of Fe for x <= 0.5 Electrical spin injection from Fe0.5Ga0.5 produces an electron spin polarization > 70% in GaAs at 20 K, similar to that obtained from Fe contacts but at out-of-plane saturation fields as low as 0.36 T rather than 2.2 T. (c) 2007 American Institute of Physics.