Ultrasonic Attenuation in Germanium at Microwave Frequencies

The attenuation of longitudinal ultrasonic waves in single‐crystal germanium has been measured at several frequencies between 0.15 and 2.84 GHz in the temperature range 10°–60°K. The measured attenuation was the same for propagation in the 〈100〉,〈110〉, and 〈111〉 crystallographic directions, and varied with temperature as T7 at the highest frequencies and lowest temperatures, and as T3 at the lowest frequencies near 60°K. The frequency dependence was less than linear at the lowest temperatures and between linear and quadratic at 60°K.