Mechanisms of nonstoichiometry in Y3Al5O12

Currently, Y2O3-Al2O3 phase diagrams do not show the technologically significant yttrium aluminum garnet (Y3Al5O12,YAG) phase as deviating from the stoichiometric ratio, i.e., YAG is always expressed as a line compound. In this paper, we not only report the synthesis of nonstoichiometric YAG, but also the use of atomistic simulation to predict the defect structure associated with the deviation. By comparing the experimental variation in the lattice parameter as a function of deviation from stoichiometry with the defect volume changes predicted by atomistic simulation, we predict that nonstoichiometry in YAG proceeds via cation antisite defects.