Elastic Constants of Thallium Single Crystals in the Temperature Range 4.2°–300°K

Abstract

The five independent elastic constants of single crystals of the hexagonal allotrope of thallium have been determined by the ultrasonic pulse-echo technique over the temperature range, 4.2°–300°K. The values at 300°K in units of 1011 dyn/cm2 are C11=4.080, C33=5.280, C44=0.726, C12=3.54, and C13=2.9. The compressibility derived from these elastic constants is in good agreement with the compressibility obtained by Bridgman from hydrostatic measurements on polycrystalline samples.