Czechoslovak Journal of Physics 46, 2227 (1996)
Ermile Gaganidze and Pablo Esquinazi
Abstract
We have measured the sound attenuation (Q-1) in the kHz-range of a re-entrant (Metglass 2826A) and a dilute spin glass (Pd(Fe)) with freezing temperatures ( Tf ) of 1.2 K and 1 mK. For the two samples Q-1 shows a broad maximum at Tf. In spite of very different Tf and one order of magnitude difference in Qmax-1, the reduced curve Q-1(T) / Qmax-l vs. T / Tf follows the same temperature dependence. We show that this dependence can be well described with a thermally activated phonon-spin relaxation time with a broad distribution of activation energies. The maximum activation energy of the distribution scales with the freezing temperature.