Abstract
The effect of the amplitude of the applied AC field on the dielectric permittivity of PbMg1/3Nb2/303 relaxor ceramics is investigated. It is demonstrated that increasing amplitude has the same effect as decreasing frequency on the maximum in the temperature dependence of the real part of the permittivity. It is shown that the obtained results are consistent with the predictions of the model employing the analogy with the domain wall motion and cannot be interpreted in terms of a thermally activated reorientation of the local spontaneous polarisation.