Epitaxial growth and magnetic properties of half-metallic Fe3O4 on GaAs(100) -: art. no. 233304

The growth and magnetic properties of epitaxial magnetite Fe3O4 on GaAs(100) have been studied by reflection high-energy electron diffraction, x-ray photoelectron spectroscopy, magneto-optical Kerr effect, and x-ray magnetic circular dichroism. The epitaxial Fe3O4 films were synthesized by in situ post growth annealing of ultrathin epitaxial Fe films at 500 K in an oxygen partial pressure of 5x10(-5) mbar. The XMCD measurements show characteristic contributions from different sites of the ferrimagnetic magnetite unit cell, namely, Fe-td(3+), Fe-oh(2+), and Fe-oh(3+). The epitaxial relationship was found to be Fe3O4(100)<011>//GaAs(100)<010> with the unit cell of Fe3O4 rotated by 45degrees to match that of GaAs(100) substrate. The films show a uniaxial magnetic anisotropy in a thickness range of about 2.0-6.0 nm with the easy axes along the [0 (1) over bar1] direction of the GaAs(100) substrate.