Effect of Sintering Temperature and Cu Substitution on the Structure of La0.7Ba0.291Ca0.009Mn1-xCuxO3 (x = 0 and 0.10) Manganite

Abstract

Series of Cu substituted manganese La0.7Ba0.291Ca0.009Mn1-xCuxO3 (x = 0 and 0.10) has been studied and it has affect in the structure. The powder sample was elaborated using sol-gel method. Samples were sintered at two different temperatures, 1173 K and 1473 K. Structures of all samples were investigated by X-ray diffraction (XRD). The Rietveld analysis of the powder x-ray diffraction shows that the samples crystallize in rhombohedral structure with R3c space group symmetry without any impurity phase. The values of tolerance factor (tG) shows that the sample without Cu substitution (tG = 0.98486) and with Cu substitution (tG = 0.980703) are still in perovskite structure. Substitution by Cu does not change the structure but it decreases unit cell volume, lattice parameters and Mn-O-Mn bond angle and increases Mn-O bond length. The result of experiments confirms that the Cu substitution at Mn-site interrupt the Mn3+-O2--Mn 4+ bridges and weaken the double exchange (DE) interaction between Mn3+ and Mn4+ ions. This phenomenon is indicated by a decrease in the bandwidth value.