Oxygen diffusion in LaMnO3 and LaCoO3 perovskite-type oxides: A molecular dynamics study

Oxygen ion diffusion in the La1-xSrxMnO3 and La1-xSrxCoO3 materials is investigated using Molecular Dynamics (MD) techniques. The results presented give both quantitative and qualitative information on the oxygen diffusion coefficients over a broad temperature range and on the structure of the crystal lattice. The pair distribution functions indicate significant disorder on the mobile oxygen sublattice especially at elevated temperatures, The simulations are used to construct Arrhenius plots of oxygen diffusion in the doped perovskites, from which we find good agreement between the calculated and experimental activation energies. In addition, useful information on the atomistic mechanisms for oxygen migration has been obtained from the analysis of ion trajectories. (C) 1996 Academic Press, Inc.