Mechanisms of oxygen diffusion in GdBaCo2O5.5 were investigated by molecular dynamics simulation. The results confirmed that the diffusion was mainly bi-dimensional, with oxygen moving on the (a,b) plane while diffusion along the c-axis was much more difficult. Between 1000 and 1600K, the activation energy for diffusion was about 0.6eV; close to experimental values. Going deeper into the oxygen diffusion mechanism, it was seen that this diffusion occurred mainly in the cobalt planes while most of the oxygen vacancies remained in the Gd planes. Analysis of oxygen motion showed that Gd planes could be seen as sources-sinks for the oxygen vacancies rather than as fast pathways.

Molecular Dynamics Simulations of Oxygen Diffusion in GdBaCo2O5.5. Hermet, J., Geneste, G., Dezanneau, G.: applied Physics Letters, 2010, 97[17], 174102