TEMPERATURE-DEPENDENCE OF THE SOUND-ATTENUATION AT THE SPILL GLASS-TRANSITION OF METALLIC SPILL GLASSES

We have measured the sound attenuation (Q(-1)) in the kHz-range of a r e-entrant (Metglass 2826A) and a dilute spin glass (Pd(Fe)) with freez ing temperatures (T-f) of 1.2 K and 1 mK. For the two samples Q(-1) sh ows a broad maximum at T-f. In spite of very different T-f and one ord er of magnitude difference in Q(max)(-1), the reduced curve Q(-1)(T)/Q (max)(-1) vs. T/T-f follows the same temperature dependence. We show t hat this dependence can be well described with a thermally activated p honon-spin relaxation time with a broad distribution of activation ene rgies. The maximum activation energy of the distribution scales with t he freezing temperature.