Energies of Mixing (Interaction Parameters), Substitution Limits, and Phase Stability of Solid Solutions Lu1 − xLnxVO4 (Ln = Ce—Yb, Sc, Y)

Abstract

The energies of mixing (interaction parameters) and temperature ranges of stability of solid solutions Lu_{1 − x}Ln_xVO₄ (where Ln is a rare-earth element (REE), scandium, or yttrium) with the zircon structure were calculated using the crystal-energy theory of isomorphous miscibility. It was shown that, with increasing atomic number of REE in the Ce—Lu series, the calculated energies of mixing and critical decomposition temperatures of the solid solutions regularly decrease. The substitution limits at various temperatures, the thermodynamic phase stability, and the temperature of transition to a metastable state were determined. The thermodynamic stability diagram of the REE vanadate solid solutions Lu_{1 − x}Ln_xVO₄ was presented. The results of the work can be used for searching the compositions of matrices and activators of new laser and other materials.