Probing exotic spin correlations by muon spin depolarization measurements with applications to spin glass dynamics

We develop a method to probe the local spin dynamic autocorrelation function, using magnetic-field-dependent muon depolarization measurements. We apply this method to muon spin relaxation experiments in the dilute Heisenberg spin glass AgMn (p at. %) at T>T-g, where the correlations of the Mn local magnetic moment are strongly nonexponential. Our results clearly indicate that the dynamics of this spin glass cannot be described by a distribution of correlation times. Therefore, we analyze the data assuming a local,pin correlation function which is the product of a power law times a cutoff function. The concentration and temperature dependence of the parameters of this function are determined. Our major conclusion is that in the temperature region close to T-g the correlation function is dominated by an algebraic relaxation term.