We report a dielectric anomaly in several perovskites at intermediate frequencies 10≤f≤${10}^7$ Hz in the temperature range 400 °C ≤T≤800 °C. We have found this dielectric maximum in more than 100 samples of various shapes and textures. This anomaly is shown to arise from a Debye dielectric dispersion that slows down following an Arrhenius law. We have established a link between this dielectric relaxation and the conductivity. We propose that it can be achieved through a space-charge model that quantitatively agrees with the experimental results in the lower temperature range.

• Received 13 September 1993

DOI:https://doi.org/10.1103/PhysRevB.49.7868