Structural and electrical transport properties of (La0.7-xYx)Ca0.3MnO3 manganites

Abstract

The effect of yttrium (Y) substitution at La-site on structural, microstructural and electrical transport properties of (La0.7-xYx)Ca0.3MnO3 (x = 0.00, 0.05, 0.10, 0.15 and 0.20) were investigated. Samples were prepared by conventional solid state reaction method and structural properties of the samples were obtained using the Rietveld refinement of X-ray diffraction data. X-ray diffraction patterns show orthorhombic distorted perovskite structures. Resistivity measurement results of the LaYCaMnO3 compounds show that metal–insulator transition temperature, TMI shifts to lower temperature while the resistivity increases by increasing Y3+ substitution. In the metallic region (T TMI), resistivity data were fitted to model of small polaron hopping conduction mechanism and the activation energy, Ea increased as Y substitutions increases. Keywords: Colossal magnetoresistance, Double exchange mechanism, Metal-insulator temperature, Activation energy, Conduction mechanism