Investigation of alkali halide crystals AX (A = Li, Na, K; X = F, Cl, Br) by elastic, mechanical and ultrasonic analysis

Abstract

Abstract The ultrasonic attenuation studies of alkali halides single crystal AX (A = Li, Na, K and X = F, Cl, Br) have been investigated along <100>, <110> and <111> directions at room temperature. For this investigation, a most appropriate potential model for studying physical studies of rock-salt type alkali halides, the Coulomb and Born–Mayer model has been used to evaluate higher order elastic constants. The second order elastic constants are used to compute the mechanical properties and ultrasonic velocities of the chosen materials. Additionally, the thermal properties have also been evaluated along different orientations. Thermoelastic loss is very small in comparison to the attenuation due to phonon-phonon interaction mechanism at room temperature. The achieved results of AX have been discussed and compared with available experimental and theoretical results.