EPR Study of TiO2 (Rutile) Doped with Vanadium

Samples of titanium dioxide, TiO2, doped with vanadium ions (0.1 a parts per thousand currency sign [V (n+)](0) a parts per thousand currency sign 5.0 at. %) at high temperature, were prepared in a polycrystalline state and investigated using X-, Q-, and W-band electron paramagnetic resonance, EPR, spectroscopy. Substitutional and interstitial V4+ centers in TiO2 lattice have been both observed in EPR spectra, and their spin-Hamiltonian parameters were calculated. Portions of paramagnetic and diamagnetic species of V (n+) ions were estimated. The effect of additional high temperature annealing on the valence state of vanadium centers is discussed.