Modeling relaxor characteristics in systems of interacting dipoles

We present a model which derives typical relaxor characteristics from simple and plausible microscopic assumptions. The model is based on charges which fluctuate thermally activated in double well potentials. The double well potentials are asymmetric due to disorder in the system. The electrostatic interaction between the charges is considered via a mean field approach. This model yields the typical relaxor features: we find high susceptibilities in a broad temperature range with dynamics following the Vogel-Fulcher law. In the framework of the model no spontaneous polarization arises at cooling without strong external field in accordance to experimental findings for relaxors. Furthermore the model yields hysteresis loops which depend on the amplitude of the external field and which become more and more thin and deformed above the maximum temperature of the susceptibility.