GROWTH AND PROPERTIES OF EPITAXIAL IRON-OXIDE LAYERS

Epitaxial layers of iron oxides have been grown on a MgO(001) substrat e by evaporating natural Fe or Fe-57 from Knudsen cells in the presenc e of a NO2 flow directed to the substrate. The resulting layers have b een investigated in situ with LEED, RHEED, AES and XPS and ex situ wit h GEMS and ion beam analysis. For substrate temperatures between 200 a nd 400 degrees C we observe RHEED oscillations during deposition, indi cative of layer-by-layer growth. By adjusting the flux of NO2 at the s urface, all stable and metastable cubic phases in the Fe-O system coul d be grown: FeO (wustite), Fe3O4 (magnetite), gamma-Fe2O3 (maghemite) and solid solutions between the latter two phases. Rutherford backscat tering spectra show a relatively high minimum yield in the channel dir ections.