Measurements of the conductivity and permittivity of samples of rutile were described. The electrical response exhibited a universal behavior in the form of power-law dependences upon frequency, which was labelled as anomalous low-frequency dispersion. Under the measuring conditions used, charge transport was due to thediffusion of ionic defects of the bulk material. Two cross-over frequencies were found that marked the transition between different diffusing regimes. One of them was restricted to small (0.5nm) structural regions in the same way as the localized motion of cations reported for ion-containing glasses. The second diffusing regime was confined to regions of 5nm-scale, which was interpreted in terms of the correlated charge motions in the observed clusters of defects (crystallographic shared planes).

Anomalous Diffusion of Defects in Rutile-Titanium Dioxide - Correlation between AC Conductivity and Defect Structures. G.Garcia-Belmonte, J.Bisquert, P.Miranzo: Solid State Ionics, 2002, 146[3-4], 367-76