Ultrasonic Attenuation in Single‐Crystal Cadmium

The attenuation of compressional and shear waves has been measured in cadmium single crystals at 300°K over the frequency range from 5 Mc/sec to approximately 60 Mc/sec. Above 20 Mc/sec attenuation follows the power law α=Cfn, where α is the attenuation, f is the frequency, n is a constant between one and two, and C a second constant. The results, however, cannot be accounted for by known thermoelastic losses in the case of compressional waves and dislocation damping in the case of shear waves. The phase velocities of all five modes of propagation were determined at 300°K and used to compute the adiabatic elastic constants C11, C12, C33, and C44.