Growth of iron oxides on Ag(111) — Reversible Fe2O3/Fe3O4 transformation

Iron oxide thin films were grown by multiple cycles of iron deposition and oxidation at different annealing temperatures. The oxide layers were characterized in-situ by X-ray diffraction and LEED and after the preparation ex-situ by confocal Raman microscopy. The results show that well ordered films of wüstite, magnetite, and hematite can be grown on Ag(111). Wüstite was observed at the initial stages of growth for films of ~ 10 إ thickness prior to magnetite formation. Magnetite films of several unit cells thickness were grown and studied by XRD and Raman spectroscopy. The magnetite films could be oxidized to epitaxial hematite films at low oxygen pressures. For our films, transformation from magnetite to hematite is reversible by annealing in UHV.