Interfaces in disordered media, energy distribution and ac response

Abstract

We investigate the contribution of domain wall motion to low-frequency ac susceptibility. At low frequency the response is due to the stochastic motion of pinned domain walls, which can be viewed as hopping movements of an elastic interface between different minima of the energy landscape. Using the concept of waiting time distributions, which is related to the energy distribution of an elastic interface in disordered media, we derive the power-law behaviour of the ac response observed recently in some ferroelectrics below the Curie temperature.