Calculation of the non-linear relaxational acoustic attenuation in glasses

The non-linear relaxational acoustic attenuation in amorphous materials is calculated by a perturbation method. A saturation of the attenuation is found for insulating glasses. On the contrary an increase of attenuation is obtained in ideal glassy metals where relaxation is due to electrons only. In the case of real amorphous metals, where both electrons and phonons are active in the relaxation process, the previous two behaviours are obtained, depending on the temperature range. The comparison with experimental results indicates that a purely relaxational attenuation process is not sufficient to explain the observed features. A more complicated mechanism (where both resonant and relaxational processes are present) has to be considered. J. Physique 47 (1986) 1731-1740 OCrOBRE 1986, Classification Physics Abstracts 61.40D 43.25