Role of point defects in the physical properties of fluorite oxides

For the first time, explicit, analytical expressions have been derived for the dependence of electrical conductivity, chemical expansion, and elastic modulus on defect concentration and oxygen partial pressure using a consistent approach. The models have been validated with experimental data for Ce0.9Gd0.1O1.95-delta (GDC) with consistently good fits. In developing the model, expressions were first derived for the functional dependence of defect concentration on the oxygen partial pressure (P-O2) for n-type fluorite oxides. Expressions for the chemical expansion, elastic modulus, and electrical conductivity as functions of defect concentration are then derived and verified with experimental data.