Anderson-Grüneisen parameter δ and the temperature dependence of the bulk modulus of some fluorides

Abstract

The Anderson-Grüneisen parameter δ has been evaluated for NaF, BaF₂ and CaF₂ from the measured third-order elastic constants of these crystals. Using these δ values, the temperature dependence of the bulk modulus of these three fluorides is calculated from Anderson's theory in the temperature range up to their melting points. The bulk moduli of the alkaline earth fluorides CaF₂ and BaF₂ have similar variation with temperature. The temperature variation of the bulk modulus of the alkali halide NaF deviates from those of CaF₂ and BaF₂ and this may be attributed to the difference in the crystal structures.