Molecular-beam-epitaxy growth of ferromagnetic Ni2MnGe on GaAs(001)

Single-crystal Heusler alloy Ni2MnGe thin films have been grown on GaAs(001) by molecular-beam epitaxy. X-ray diffraction and transmission electron microscopy were used for postgrowth structural characterization. The Ni2MnGe grew in a tetragonally distorted L2(1)-like structure (a=5.65 Angstrom, c=5.96 Angstrom) with the c axis perpendicular to the film surface. An in-plane ordering with 2x periodicity and an out-of-plane ordering with 3x periodicity was observed for the as-grown films. Magnetometry measurements performed at 50 K indicate that the films are ferromagnetic and have a weak in-plane anisotropy with a coercivity similar to5.5 Oe and saturation magnetization of similar to450 emu/cm(3). The Curie temperature was measured to be similar to320 K. (C) 2003 American Institute of Physics.