The diffusion of O in yttria-stabilized material was investigated by using molecular dynamics simulation techniques. It was assumed that the O ions migrated via a discrete hopping process, mainly between neighboring tetrahedral sites, and diffusion appeared to occur over both short-term and long-term regimes. A linear relationship was found, between the mean-square displacement and time, only when the O ions had moved through distances which were much greater than the characteristic distance of the underlying crystal structure. The O tracer diffusivities, in the long-term regime, were equal to 1.86 x 10-6 and 3.23 x 10-6cm2/s at 1759 and 2057K, respectively. The ionic conductivity, when deduced from the long-term diffusion regime, agreed well with experimental data.

H.W.Brinkman, W.J.Briels, H.Verweij: Chemical Physics Letters, 1995, 247[4-6], 386-90