AC switching of relaxor PLZT ceramics

The switching under application of bipolar ac field is studied by recording of the hysteresis loops in wide temperature and field range in PLZTx/65/35 ceramics. The qualitative differnce of the shape of hysteresis loops above and below the freezing temperature is attributed to backswitching in relaxor phase due to the depolarization field produced by the bound charges located at the interphase boundaries. The application of the quasistatic approach to analysis of the experimental data allows us to obtain parameters of the distribution function of local coercive fields fi-om the field dependence of the switching charge derivative onfield.