Growth, structure, and magnetic properties of gamma-Fe2O3 epitaxial films on MgO

Single-crystal epitaxial thin films of gamma-Fe2O3(001) have been grown on MgO(001) using oxygen-plasma-assisted molecular beam epitaxy. The structure and magnetic properties of these films have been characterized by a variety of techniques, including reflection high-energy electron diffraction (RHEED), low-energy electron diffraction (LEED), x-ray photoelectron spectroscopy and x-ray photoelectron/Auger electron diffraction (XPD/AED), vibrating sample magnetometry, and ferromagnetic resonance. Real-time RHEED reveals that the film growth occurs in a layer-by-layer fashion. The gamma-Fe2O3(001) film surface exhibits a (1 x 1) LEED pattern. The growth of gamma-Fe2O3 films at 450 degrees C is accompanied by significant Mg outdiffusion. AED of Mg KLL Auger emission reveals that Mg substitutionally incorporates in the gamma-Fe2O3 lattice, occupying the octahedral sites. Magnetic moments are similar to 2300 G and similar to 4500 G for gamma-Fe2O3 films grown at 250 degrees C and 450 degrees C, respectively. The high magnetic moment for the films grown at 450 degrees C could be attributed to the high degree of structural order of the films and Mg substitution at octahedral sites. (C) 1997 American Institute of Physics.