Elastic Constants of Strontium Fluoride Between 4.2 and 300°K

Abstract

The elastic constants of single-crystal Sr${\mathrm{F}}_2$ have been determined over the temperature range 4.2-300°K, by an ultrasonic pulse-echo technique. The values of the elastic constants, extrapolated to 0°K, in units of ${10}^{11}$ dyn/${\mathrm{cm}}^2$, are: $c_{11}=12.88\mathrm{}$, $c_{12}=4.748\mathrm{}$, and $c_{44}=3.308\mathrm{}$. From these values, a Debye temperature of 380°K is calculated for Sr${\mathrm{F}}_2$ at 0°K. The elastic constants of Sr${\mathrm{F}}_2$ are computed theoretically from a rigid-ion model, and the results are compared with the experimentally measured values. The elastic constants of Sr${\mathrm{F}}_2$ are compared with those of the other alkaline-earth fluorides.