Description:
<jats:p>A statistical thermodynamic model of the nonstoichiometry in ABO3 compounds possessing volatile AO species is applied to mass−loss Knudsen effusion experimental (p,T,x) data. Good qualitative agreement is found between the model and the experiment. The nonstoichiometry is assumed to be accommodated by randomly occurring uncharged Schottky defects with an energy of formation about +0.5 eV/defect and an interaction energy of about −0.1 eV/defect pair. However, the theoretical model deviates from the experimental data describing the relationship between vapor pressure and the PbTiO3 defect concentration. This observation suggests that some refinements in the model (such as a consideration of the ordering and/or charging of lattice vacancies) will be necessary.</jats:p>