Atomistic simulations which were based upon energy minimization techniques were used to study the energetics which were associated with M2O3 solution. The results predicted that the binding energy of an O vacancy to 1 or 2 substitutional cations was a sensitive function of the dopant cation radius. The O vacancies occupied sites which were first-nearest neighbour with respect to small dopants, whereas the O vacancies were located in second-nearest neighbour sites with respect to large dopants. A cross-over occurred for Sc3+; which also exhibited the lowest binding energy. This behaviour was the result of a long-range relaxation of the O sub-lattice. The model was confirmed by comparing the predicted lattice parameters, of ZrO2-M2O3 solid solutions, with experimental data.

Defect Cluster Formation in M2O3-Doped Cubic ZrO2. M.O.Zacate, L.Minervini, D.J.Bradfield, R.W.Grimes, K.E.Sickafus: Solid State Ionics, 2000, 128[1-4], 243-54