Dislocation Interactions with Phonons in Sodium Chloride in the Temperature Range 70-300°K

The dislocation drag coefficient $B$ in sodium chloride has been measured in the temperature range 70-300°K. Use was made of a technique for measuring ultrasonic attenuation changes $\Delta \alpha$, at different frequencies, caused by a bias stress. The numerical values of $B$ were obtained from an analysis which does not require any knowledge of the dislocation density or of other geometrical features of the dislocation network. The experimental results agree qualitatively with theoretical predictions of the temperature dependence of $B$. The dislocation scattering cross section for phonons is deduced from these measurements and compared with theoretical treatments.