Enhancing Pr 1-x Ba x MnO 3-δ perovskite charge-transport by electronic structure modulation

Research has shown half (Pr 0.5 Ba 0.5 MnO 3-δ ) perovskite to exhibit good electronic and magnetic properties. However, it is necessary to clarify whether electronic transport originates in the cubic or hexagonal phase. This paper explores Ba-doped Pr 1-x Ba x MnO 3-δ ( x = 0.35, 0.4, 0.45 and 0.5) disordered perovskites with mixed valence states. The cubic-phase transition increases when the EDTA sol–gel synthesis method was used. Electrical conductivity studies demonstrate that cubic Pm3m space group symmetry with a little number of oxygen vacancies enhances conductivity. The origin of this process has been explained in terms of the transition from Mn 4+ → Mn 3+ ions forming hopping sites for electrons/holes. Rietveld refinement, HRTEM, and XPS confirm a complete structure transition to single cubic perovskite. Charge carrier transport clarifies that the cubic perovskite structure enhances the electrical conductivity more effectively than their cubic/hexagonal mixture counterparts. Our results suggest that the activation energy for electron transport is independent of symmetry but not of Pr 3+ concentration. Electrical conductivity increases up to twice as much (182 Scm −1 ) suggested by previously published research, ratifying its potential application as a cathode for SOFC.