Electrical properties of Sn-doped Ba0.75Sr0.25Ti0.95O3 perovskite

The aim of this paper is to study the structural and the electrical properties of Ba0.75Sr0.25Ti0.95Sn0.05O3 system, synthesized by the solid state reaction method. The material was structurally characterized by X-ray diffraction and transport measurements have been made using impedance spectroscopy technique. From DC conductance analysis, we found that insulator-metal transition is not observed in the temperature range of the study. The electronic conduction has two different processes. The first one is dominated by thermally activated hopping of small polaron, at high temperatures, and another one by variable range hopping, at low temperatures. Impedance spectrum results indicated that the electrical properties are strongly dependent on temperature. Nyquist plots showed that the dielectric response is accurately fitted by the Cole-Cole model and represented by an equivalent circuit which consists of a parallel combination of a resistance and a constant phase element. From this analysis, the evidence of grain boundary conduction has been observed.