Thermal conductivity and ultrasonic attenuation

Ultrasonic attenuation in crystals is usually analyzed using theories which incorporate phonon relaxation processes. These relaxation processes are also important to the lattice thermal conductivity. However, the relaxation times derived from thermal conductivity measurements are often complicated averages since various processes and various lattice modes are involved. The usefulness of thermal conductivity measurements in determining ultrasonic properties in both the high-temperature (ωt < 1) and low-temperature (ωt > 1) regions will be discussed. Examples will be taken from a variety of materials.