845-849The
ultrasonic phonon-viscosity loss and thermo-elastic loss have been studied in
octahedral semiconductors along, and
crystallographic directions as a function of high temperature (=300K). For this
evaluation, the
temperature dependence of
second- and third-order elastic constants starting with two basic parameters
has been computed. The thermo-elastic loss is very small as compared to
phonon-viscosity loss. The behaviour of temperature dependence of ultrasonic
attenuation is the same as in other semiconducting materials.</span