Nonstationary spin glass dynamics from susceptibility and noise measurements

Abstract

Nonstationary dynamics has been observed in very-low-frequency (10−2–10−1 Hz) ac susceptibility and noise measurements on the thiospinel CdCr1.7 In0.3 S4 spin glass. The time relaxation of the ac susceptibility yields a large decrease of the out-of-phase component χ″ towards a finite stationary value. The relaxation of the spectral density of the magnetization derived from zero-field noise measurements is in remarkable agreement with the behavior of χ″. The observed time dependence compares well with the predictions from the thermoremanent magnetization decay analyses. In the range of times of χ″ measurements, the linear-response theory applies to the nonstationary dynamics.