NMR Studies of Spin-Glass Dynamics

Abstract

The dynamics of Mn impurities in dilute $\mathrm{Cu}\mathrm{Mn}$ (12, 20, and 43 ppm) have been studied in the spin-glass regime, down to $\ensuremath{\sim}\frac{{T}_{G}}{30}$. In an applied field of 275 Oe, the spins freeze gradually although their motions are highly correlated below a well-defined temperature ${T}_{G}$, which is the same as that found in static susceptibility measurements. At ${T}_{G}$, no anomaly is found on the impurity correlation time ${\ensuremath{\tau}}_{e}$, which is field dependent.