High-quality epitaxial iron nitride films grown by gas-assisted molecular-beam epitaxy

Thin films of gamma'-Fe4N were grown on polished (001) MgO substrates by mo lecular-beam epitaxy of iron in the presence of a gas flow from a rf atomic source. By means of x-ray diffraction, Mossbauer Spectroscopy, Rutherford backscattering/channeling, and scanning probe microscopy, it is shown that, with this method, single-phase, high-quality epitaxial thin films can be g rown with a very smooth surface (root-mean-square roughness similar to0.4 n m). Magnetic measurements reveal square hysteresis loops, moderate coercivi ties (45 Oe for a 33 nm thick film) and complete in-plane orientation of th e magnetization. These properties make the films interesting candidates for device applications. (C) 2001 American Institute of Physics.