Simulations which were based upon energy minimization techniques were used to study the energetics that were associated with the addition of other oxides. The results showed that the binding energy of an O vacancy to one or two substitutional cations was a strong function of the dopant cation radius. That is, small dopant ions preferred to occupy first-nearest neighbour sites, while large dopant ions preferred second-nearest neighbour sites. The cross-over occurred at about Gd3+; which also exhibited the smallest binding energy. The results were used to predict the lattice parameter as a function of the defect concentration.

Defect Cluster Formation in M2O3-Doped CeO2. L.Minervini, M.O.Zacate, R.W.Grimes: Solid State Ionics, 1999, 116[3-4], 339-49