On the dynamics of the magnetic hyperfine interaction in the cluster glass Y_1.1(Fe_0.75Al_0.25)₂ above the freezing temperature

⁵⁷Fe Mossbauer measurements were performed in applied fields up to 13.5 T in the temperature range 45<T<300 K. Whereas at high temperatures the recorded spectra could be analysed using a set of subspectra with intensity ratios according to a binomial distribution taking into account nearest-neighbour environments, at lower temperatures the line shape indicates the presence of relaxation effects. For this temperature region a model is proposed, in which magnetic clusters are formed stochastically. These clusters are assumed to decay after a mean lifetime, which increases with increasing applied field and decreasing temperature.