Non-exponential relaxation in dilute antiferromagnets

Dilute Ising antiferromagnets in a homogenous magnetic field have a disorde red phase for sufficiently large values of the field and for low temperatur es. Here, the system is in a domain state with a broad size-distribution of fractal domains. We study the relaxation dynamics of this domain state aft er removing the external field for two and three dimensions. Using Monte Ca rlo simulation techniques, we measure the decay of the remanent magnetizati on. Its temperature dependence can be understood as thermal activation. All data can be described by a unique generalized power law for a wide range o f temperatures in two- and three-dimensions. The question of whether the ex ponent of the generalized power-law is universal remains open.