Diffusion of Oxygen Vacancies in Reduced Rutile (TiO₂)

Abstract

Diffusion coefficients of point defects in reduced rutile (TiO 2 ) due to the reduction in vacuum of 4×10 -9 Torr with the ion pump in the temperature range 800°C–1100°C were studied. The coefficients along c and a -axes are \begin{aligned} D_{c}{=}147\exp\left(-\frac{2.4{\pm}0.3}{kT}\right)\ \text{and}\ D_{a}{=}91\exp\left(-\frac{2.4{\pm}0.3}{kT}\right). \end{aligned} The activation energies are very close to tat of O 18 in rutile by Haul and Dümbgen. Diffusions are discussed in terms of oxygen vacancies from the crystal orientation dependence of the coefficients and the activation energies. It is concluded that the result in this experiment gives the clear evidence of the presence of oxygen vacancies in reduced rutile and their migration energies are 2.4 eV.