A Combined Total Scattering and Simulation Approach to Analyzing Defect Structure in Bi₃YO₆

The defect structure and electrical properties of the fast oxide ion-conducting solid electrolyte δ-Bi 3 YO 6 have been studied using a combination of total neutron scattering analysis, energy minimization methods, and AC impedance spectroscopy. Conventional structural analysis using the Rietveld method reveals the oxide ions to be distributed over three crystallographic sites at room temperature, with a small change in this distribution at 800 °C. Analysis of short-range correlations using a total neutron scattering approach yields information on Bi and Y coordination environments. Careful analysis of the angular distribution functions derived from reverse Monte Carlo modeling of the total scattering data reveals physical evidence for a predominance of ⟨110⟩ vacancy ordering in this system. This ordering is confirmed as the lowest energy configuration in parallel energy minimization simulations.