Nanoscale Phase Separation in Fe(sub 3)O(sub 4)(111) Films on Sapphire(001) Grown by Oxygen-Plasma-Assisted Molecular Beam Expitaxy

摘要

We report a phase instability in oxygen-plasma-assisted molecular beam epitaxy of magnetite films on sapphire substrates. Under a wide range of growth conditions, magnetite films phase separate, on a nanometer length scale, into magnetite and metallic Fe, which is attributed to formation of the thermodynamically unstable phase in the initial stages of growth.