Complex impedance, dielectric relaxation and electrical conductivity studies of Ba_1-xSr_xTiO₃ceramics

Abstract

In this work, we prepared series of Ba1-xSrxTiO3 (BSxT) powders, with different strontium concentrations (x = 0, 0.025, 0.75, 0.10, 0.125 and 0.15), by the sol-gel method. The variation of structure in the Ba1-xSrxTiO3 system was analyzed using XRD and Raman techniques. The field dependence of dielectric relaxation and conductivity was measured over a wide frequency range from room temperature to 400 °C. The activation energy, calculated from the thermal variation of the conductivity for different frequencies, showed that the Sr has significant effects on the properties of BaTiO3. Relaxation times extracted using the imaginary part of the complex impedance (Z''(ω)) and the modulus (M''(ω)) were also found to follow the Arrhenius law and showed an anomaly around the phase transition temperature.