Evidence for Power-Law Spin-Correlation Decay from Muon Spin Relaxation in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Ag</mml:mi><mml:mi mathvariant="normal">Mn</mml:mi></mml:math>Spin-Glass

Abstract

Muon spin relaxation measurements have been carried out below the "glass" temperature ${T}_{g}$ in $\mathrm{Ag}\mathrm{Mn}$ spin-glasses. The muon spin-lattice relaxation rate varies with field $H$ as ${H}^{\ensuremath{-}0.46\ifmmode\pm\else\textpm\fi{}0.05}$ for $0.30&lt;~\frac{T}{{T}_{g}}&lt;~0.66$. This suggests that impurity-spin correlations decay with time as ${t}^{\ensuremath{-}\ensuremath{\nu}}$, $\ensuremath{\nu}\ensuremath{\simeq}0.54\ifmmode\pm\else\textpm\fi{}0.05$, in contrast to the more usual exponential decay. The present data therefore agree quantitatively with the prediction $\ensuremath{\nu}\ensuremath{\simeq}\frac{1}{2}$ of mean-field dynamic theories.