Nanoscale phase separation in Fe₃O₄(111) films on sapphire(0001) and phase stability of Fe₃O₄(001) films on MgO(001) grown by oxygen-plasma-assisted molecular beam epitaxy

A phase instability in oxygen-plasma-assisted molecular beam epitaxy of Fe3O4 films on sapphire (0001) substrates was investigated. Growth conditions were specified for which single-phase, epitaxial Fe3O4 (111) films can be grown by plasma-assisted molecular beam epitaxy. It was shown that single-phase Fe3O4 (111) films are more difficult to magnetize than Fe3O4 (001) films.