Oxygen ionic transport in LaInO3 and LaIn0.5Zn0.5O2.75 perovskites: Theory and experiment

The new oxygen-deficient orthorhombic perovskite LaIn0.5Zn0.5O2.75 was obtained by solid-state synthesis. Ionic transport properties were studied by a combined theoretical approach consisting of geometrical-topological analysis, bond valence site energy modeling and density functional theory (DFT) calculations. The DFT calculations showed that oxygen migration energy is by 0.2 eV lower for zinc-containing perovskite compared to pure LaInO3. The conductivity was measured in the temperature range of 400–1000 °C and at various oxygen partial pressures 10−18–2·10−1 atm. LaIn0.5Zn0.5O2.75 was found to be pure oxide-ion conductor (σ ≈ 10−5 S/cm) at T < 550 °C in air with the experimental ionic activation energy of 0.79 eV compared to 0.97 eV for LaInO3, which is in agreement with our theoretical prediction. With increasing the temperature the share of the hole conductivity of LaIn0.5Zn0.5O2.75 increased.