Perpendicular magnetization of Co20Fe50Ge30 films induced by MgO interface

Epitaxial growth of Co20Fe50Ge30 thin film on single crystal MgO (001) substrate is reported. Structure characterization revealed (001)-oriented B2 order of CoFeGe well lattice matched with the MgO barrier. Perpendicular magnetic anisotropy (PMA) was achieved in the MgO/CoFeGe/MgO structure with an optimized magnetic anisotropy energy density (K) of 3 106 erg/cm3. The magnetic anisotropy is found to depend strongly on the thickness of the MgO and CoFeGe layers, indicating that the PMA of CoFeGe is contributed by the interfacial anisotropy between CoFeGe and MgO. With reported low damping constant, CoFeGe films are promising spintronic materials for achieving low switching current.