Structural and Magnetic Properties of Fe-Doped Anatase TiO2 Films Annealed in Vacuum

Structural and magnetic properties of Fe-doped anatase TiO2 films fabricated by sol-gel spin coating are investigated. X-ray diffraction measurements reveal that Fe3+ ions are incorporated into the TiO2 lattice. No ferromagnetism-related secondary phases and magnetic nanoparticles are observed in the films. The presence of electron paramagnetic resonance signals at g ~ 2.0 supports oxygen vacancies and/or defects generated in the films after annealing in vacuum. Magnetic measurements indicate that Fe-doped anatase TiO2 films are ferromagnetic at room temperature. These observations suggest that oxygen vacancies and/or defects are energetically favorable for the long range Fe3+-Fe3+ ferromagnetic coupling in Fe-doped anatase TiO2 films.