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 ...
Reports by Author
