Jahn-Teller distortion effects on the transport properties of La0.7Ca0.3Mn1-xFexO3 perovskite NPs

This paper presents an examination of La0.7Ca0.3Mn1-xFexO3 (x = 0, 0.005, 0.01, 0.015 and 0.02) nanoparticles (NPs) with a single perovskite-type structure. Rietveld refinement confirms an orthorhombic structure with Pnma space group symmetry. An increase of the Fe3+ cation in lower concentrations provokes a reduction of the Jahn-Teller distortion, and consequently induces an increase in the tolerance factor, therefore, decreasing its unit-cell volume. The complex-plane impedance results indicated a semiconductor behavior thermally activated between 143 and 300 K. The activation energy (E-h) using a small polaron hopping model was found to increase proportionally to the increase in Fe3+-doped concentration. Above T sigma the sigma(T) behavior has been explained based on theVRHmodel, while in a temperature range below T-c using the SPH model. The findings reveal a strong influence of Fe concentration, which decreases the density of states at the Fermi level.