Phase equilibria and defect interactions in the cubic Gd{sub x}Zr{sub 1-x}O{sub 2-x/2} system with empirical potentials

Lattice models are powerful tools for studying configurational thermodynamics. For many years these models have been successfully applied in many binary and ternary metallic systems to study phase equilibria with little or no experimental input. Recently, the same models have been shown to work very well in ceramic systems including high temperature superconductors, and the MgO-CaO system. Two developments have made the extension of these models to systems with aliovalent doping practical. First, aliovalent systems can be treated as coupled binary systems with the same techniques as simple binary systems. Second, it has been shown that the conditionally convergent coulomb interactions can be well mated with short-ranged effective interactions. In this paper, we use a lattice model with which the pyrochlore to defect fluorite transition and defect interactions at any concentration or temperature can be studied with a no priori assumptions.