Above room temperature complex impedance analysis of properties of La0.33Sr0.67Mn0.33Ti0.67O3±δ perovskite

ABSTRACTLa0.33Sr0.67Mn0.33Ti0.67O3±δ perovskite was prepared by the standard solid state reaction at 1773 K. The sample crystallizes in the cubic Pm3-m structure. The electrical properties of the sample have been investigated above room temperature in 293–373 K range with varying frequency between 102 and 106 Hz using complex impedance analysis. The sample exhibit a metal–semiconductor transition temperature at TMS = 303 K. The conductance curves were well fitted by Jonscher power law G(ω) = Gdc + Aωn, which shows that with increasing temperature, the exponent (n) decreases below TMS, and increases above TMS. The activation energy deduced from the analysis of the conductance curves matches very well with the value estimated from the relaxation time indicating that relaxation process and electrical conductivity are attributed to the same defect. Nyquist plots of impedance show semicircle arcs for sample and an electrical equivalent circuit has been proposed to explain the impedance results.