Anomalous frequency dependence of magneto-electric effect in doped DTN

The anomalous frequency dependence observed for the magneto-electric effect in the Bose glass state of dichlorotetrakis-thoiurea-nickel doped with bromine is analyzed in terms of the hierarchical droplet model of spin glasses. In this model low energy barriers must be overcome before accessing higher energy states leading to scaling laws for the spin correlation functions and an associated frequency dependence for transition rates.