Ferromagnetism and local electronic properties of rutile Ti1-x Fex O2 single crystals

An experimental evidence of the effects of iron on the magnetic and local electronic properties of TiO2 single crystals is provided. When ferromagnetic rutile TiO2 single crystals are doped with Fe ions, an enhancement of the saturation magnetic moment is observed, along with a transfer of electrons to Fe3d and Ti3d levels. Indeed, the analysis of core-level photoemission data shows that addition of iron has the effect (i) to promote electron charge transfer from O2p band to localized Fe3d orbitals and (ii) to reduce titanium ions by introducing 3 d1 electronic states in the otherwise empty 3d band of pure TiO2. These effects, resulting from the incorporation of both transition-metal ion dopants and oxygen vacancies, increase the local magnetic moments that can contribute to long-range ferromagnetic ordering.