Structural, electrical conductance and complex impedance analysis of (Nd1−xCex)0.7Sr0.3MnO3 (0≤x≤0.20) perovskite

Polycrystalline samples of (Nd1−xCex)0.7Sr0.3MnO3 (x=0, 0.10 and 0.20) were prepared by a high-temperature solid-state reaction technique. The X-ray diffraction study has shown that all the samples exhibit a single phase with orthorhombic structure (space group Pnma). From the resistivity data, it is found that all the samples show metal to semiconductor transition and the transition temperature decreases with the Ce doping. The complex impedance has been investigated in the temperature range 80–320 K and in the frequency range 40 Hz–1 MHz. AC conductance analyses indicate that the conduction mechanism is strongly dependent on temperature and frequency. The impedance plane plot shows semicircle arcs at different temperatures and an electrical equivalent circuit has been proposed to explain the impedance results. The activation energies obtained from the conductance is slightly higher than that from time relaxation analyses.