Epitaxial thin films of (001)-oriented FeTiO(3+delta) were prepared on alpha-Al2O3(001) single crystalline substrates by helicon plasma sputtering technique. The FeTiO(3+delta) films had large oxygen nonstoichiometry, which seriously depended on both substrate temperature and oxygen pressure during the sputtering deposition. The valence states of Fe ions in FeTiO(3+delta) changed monotonically from Fe2+ to Fe3+ with decreasing the substrate temperature from 900 to 400 degrees C or with increasing the oxygen pressure ...
CoFe2O4/alpha-Fe2O3 (ferrimagnetic/antiferromagnetism) bilayered films were prepared on alpha-Al2O3(102) single-crystalline substrates by helicon plasma sputtering. A well-crystallized epitaxial alpha-Fe2O3(102) layer was formed on the substrate, while CoFe2O4 grown on alpha-Fe2O3(102) was a polycrystalline layer with a (100)-preferred orientation. The alpha-Fe2O3(102) films without CoFe2O4 layers clearly showed a spin-flip transition at about 400 K. The spins aligned perpendicular to the film plane at room temperature changed their direction within the film plane ...
Titanium di- and sesquioxide films were epitaxially grown on the (001) surface of sapphire single-crystalline substrates by an activated reactive evaporation method. Formation range for each titanium oxide was determined as a function of oxygen presssure (P(O2)) by means of x-ray diffraction, transmission electron microscopy, and Raman spectroscopy. Films prepared at P(O2) by means>=2.0E(-4) Torr were stoichiometric (100)-oriented rutile of TiO2, and with decreasing P(O2) they would accommodate more and ...
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