Enhancing Pr1-xBaxMnO3-δ perovskite charge-transport by electronic structure modulation.

Research has shown half (Pr_0.5Ba_0.5MnO_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-xBa_xMnO_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 P m 3 ¯ m 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 Mn⁴⁺ → Mn³⁺ 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 Pr³⁺ 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. [ABSTRACT FROM AUTHOR]