Fe-doped TiO2 rutile thin films were fabricated by reactive magnetron sputtering on SiO2 substrates under different growth conditions, and the structure and magnetism were systematically investigated. X-ray diffraction data, atomic force microscopy, and magnetic force microscopy confirmed the absence of metallic Fe clusters or any other impurity phase. The divalent Fe ion was identified by X-ray photoelectron spectra. Room-temperature ferromagnetism was observed for all the FexTi1−xO2 (x = 3 to 15%) rutile films. However, the saturation magnetization (Ms) varied drastically for different pressures, doping concentrations, and annealing processes. The results show that ferromagnetism originated from the doped matrix rather than any type of magnetic cluster and the ferromagnetism was strongly correlated with the O vacancies in TiO2.

Role of Oxygen Vacancies on Ferromagnetism in Fe-Doped TiO2 Thin Films. Deng, H.Q., Ou, D.R., Jia, Q.S., Yao, X.D., Zhuo, M.J., Li, X.B.: Journal of Applied Physics, 2007, 102[7], 073905