Dämpfung von Hyperschall in dünnen Silberschichten bei 9 GHz

The attenuation of longitudinal hypersonic waves (8.4–10.0 GHz) in thin polycrystalline silver films has been measured in the temperature range from 4 to 26 ?K. The silver films with thicknesses between 0.2 and 3.0 Μ. were evaporated on the optically flat polished end surface of a cylindrical quartz transducer. The measured value of the attenuation coefficient α=1.5·10⁴ dB cm^?1 is much higher than the theoretically predicted value due to electron-phonon interaction. Furthermore the measured value α is independent of temperature and increases with the square of frequency. Presumably this attenuation of hypersonic waves in polycrystalline silver films is due to scattering processes at lattice defects.