The Effect of Ion Size on Solution Mechanism and Defect Cluster Geometry

Atomistic simulation calculations are used to predict the solution mechanisms and the defect cluster geometries of: M²⁺ dopant cations in Y₂O₃, M³⁺ dopant cations in CoO and M²⁺ dopant cations in SrTiO₃. The interatomic potential parameters were derived by simultaneously fitting the properties of a range of mixed cation materials. The results suggest that although both solution enthalpies and cluster binding energies do scale with ionic radius, the relationships can be quite complex, materials specific and will not necessarily exhibit simple minima when the radius of the host cation equals the dopant cation, as described in previous studies.