The Meyer–Neldel rule in amorphous TiO 2 films with different Fe content

Amorphous titania thin films with increasing Fe content have been prepared by RF magnetron sputtering. X-ray absorption spectroscopy revealed modifications of both local structures/environment of the Ti and Fe atoms, with formation of phases containing amorphous material and a magnetite-like phase. The temperature dependence of the electrical conductivity of the films was investigated for temperatures higher than half of the Debye temperature (T . 391 K). It was found that the electrical conductivity in the amorphous Fe/TiO2 films obeys the Meyer–Neldel rule. The origin of this behavior is explained on the basis of the multiphononassisted hopping model.