Effect of Pr substitution on structural and dielectric properties of SrTiO3

Pr-doped SrTiO3 ceramics were fabricated by the conventional solid-state reaction method. Pr-doping greatly decreased the lattice parameters and the average grain size of SrTiO3 ceramics sample. Two thermally activated dielectric relaxations were found for the low- and high-temperature relaxations, respectively. By means of a detailed analysis, the low-temperature relaxation was ascribed to the electric hopping between Pr3+ and Pr4+ induced by the Pr-doping, and the origin of the high-temperature relaxation was changed from oxygen vacancies to the polar nanoregions with the increase of Pr content.