Impact of La doping on the crystalline phase and mixed ionic-electronic conductivities of Ba_0.5-xLa_0.5+xFeO_{3- (0x0.3) solid solution}

This study discusses the preparation of lanthanum-doped barium ferrite following the solution combustion procedure. The solid solution of A-site elements in Ba0.5-xLa0.5+xFeO3-delta (0 <= x <= 0.3) has been explored. The synchrotron x-ray powder diffraction data and relevant Rietveld refinement indicate that the crystallographic configuration transformed from cubic to orthorhombic for x > 0.1. Because La-doping decreases structural symmetry on the crystal lattice resulting in a reformed structural phase. A dense microstructure was obtained for all the samples, where optimum grain growth was observed for an equal amount of Ba and La in the A-site. The highest oxygen deficiency of 50 mol% La-doped sample was confirmed by Thermogravimetric analysis. The highest total electrical conductivity of 226.2 S/cm at 450 degrees C and the highest oxygen permeability of 248 nmol/cm(2)/s at 950 degrees C exhibited by 50 mol% La-doped sample indicating potentiality as an air-electrode of solid oxide fuel cells.