Structural and Electrical Conductivity Analysis of the Perovskite La$_{0.65}$Pr$_{0.1}$Ba$_{0.25}$Mn$_{1-x}$Ga$_{x}$O$_{3}$

Abstract

The structural and electrical properties of La$_{0.65}$Pr$_{0.1}$Ba$_{0.25}$Mn$_\mathrm{1-x}$Ga$_\mathrm{x}$O$_{3}$(x= 0, 0.05 and 0.15) nano-crystalline manganite have been studied systematically. The doped compositions were successfully synthesized by the Pechini sol-gel technique at 1273K and then characterized by x-ray diffraction (XRD), Scanning electron microscopy (SEM), AC impedance and DC conductivity. Rietveld refinement of XRD patterns revealed that all technique orthorhombic structure with Pnma space group. AC impedance studies revealed their semi-conducting behavior in air. Complex impedance plots exhibit semicircular arcs described by an electrical equivalent circuit. Off–centered semicircular impedance plots show that the Ga-doped compounds obey a non-Debye relaxation process. The activation energies calculated from the electrical conductivity is lower than these calculated from relaxation time. This indicates that the same type of charge carriers is responsible for both electrical conduction and relaxation phenomena.