Ultrasonic Attenuation in Pure and Doped n -Type Germanium

Attenuation suffered by compressional and shear acoustic waves propagating along the $〈100〉$ and $〈110〉$ directions has been evaluated from measured third-order elastic moduli for germanium metal in its pure and doped states at room temperature. The present results for pure germanium are in excellent agreement with previous attenuation measurements. As an effect of doping, an increase in phonon viscosity and in thermoelastic attenuation is observed. The resisting force acting against moving dislocations of both types is also presented.