Sol-gel synthesis and impedance studies of perovskite Pb_(1-x)(Na_0.5Sm_0.5)_xTiO₃ ceramics

Sodium and samarium substituted PbTiO₃ ceramics Pb_(1-x)(Na_0.5Sm_0.5)_xTiO₃ for x = 0.30 and 0.40 compositions have been synthesized using sol-gel process. The present investigation focus on the temperature-dependent relaxation process and impedance studies of PNST ceramics. Two semicircular arcs were observed in Nyquist plot. Fitting of impedance data using Cole-Cole equation was used to separate the grain and grain boundary contribution to total impedance. The overall conductivity decreases with an increase in substitution. At 410 °C the conductivity varies from 3.7×10^-7 Ω^-1cm^-1 to 1.9×10^-7 Ω^-1cm^-1 for x = 0.30 to x = 0.40 respectively.