The dielectric relaxation phenomenon was studied in lanthanum modified lead zirconate titanate ceramics in the high temperature para-electric phase. The high temperature dielectric response revealed an anomalous behavior, which was characterized by an increase of the real component of the dielectric permittivity with the increase of the temperature. At the same time, a similar behavior, with very high values, was observed in the imaginary component of the dielectric permittivity, which could be associated with conduction effects related to the conductivity losses. The frequency and temperature behavior of the complex dielectric permittivity was analyzed considering the semi-empirical complex Cole–Cole equation. The activation energy value, obtained from the Arrhenius’ dependence for the relaxation time, was found to decreases with the increase of the lanthanum concentration and was associated with single-ionized oxygen vacancies. The short-range hopping of oxygen vacancies was considered as the main cause of the dielectric relaxation.

Dielectric Relaxation Related to Single-Ionized Oxygen Vacancies in (Pb1−xLax)(Zr0.90Ti0.10)1−x/4O3 Ceramics. A.Peláiz-Barranco, J.D.S.Guerra: Materials Research Bulletin, 2010, 45[9], 1311-3