Spin glass dynamics above Tg: a μSR study of AgMn

In this work we use the zero and longitudinal field muon spin relaxation technique to map the Fourier transform of the spin-spin dynamical autocorrelation function q(ω)) in the metallic spin glass AgMn(0.5 at %) at T > Tg. We find that at high longitudinal field the muon polarization obeys a time-field scaling relation (see Fig. 1) which could be explained by a power law decay of q(ω)) while in zero field the muon relaxation is finite implying that q(ω) is bound. We therefore conclude that q(ω)), at T > Tg, is best described by a cut off power law correlation function. We contrast our findings with spin glass models