The antiphase domain structure in epitaxial Fe3O4 films determines its physical properties such as super-paramagnetism, resistivity, and magnetoresistance. A good knowledge and control of the domain sizes in these films was therefore of utmost importance. It was found that the antiphase domain boundaries annealed out via a diffusive mechanism at relatively low temperatures. This was demonstrated by post-annealing the films at 250, 300 and 350C. The boundary migration process was a thermally activated process with an activation energy of 26kJ/mol (0.25eV). The domain size in epitaxial Fe3O4 films was further studied as a function of the growth parameters. A linear relationship was obtained for the logarithm of the domain size versus the inverse of the growth temperature (in the range of 125 to 300C), which supports the diffusional mechanism. The domain size was not influenced by the Fe flux, but did depend upon the O flux. This suggested that the critical nuclei were pairs of Fe and O atoms and that Fe was more mobile than O.

Diffusive Motion of Antiphase Domain Boundaries in Fe3O4 Films. W.Eerenstein, T.T.M.Palstra, T.Hibma, S.Celotto: Physical Review B, 2003, 68[1], 014428 (7pp)