Contribution of reversible processes to the non-linear dielectric response in hard lead zirconate titanate ceramics

The dependence of the dielectric constant and its losses on the applied field is studied, as well as the correlation between the dielectric constant and dielectric losses. The results show that hard lead zirconate titanate cannot be described by the Rayleigh model, so the hysteretic response of those materials cannot be attributed exclusively to the contribution of the irreversible processes. The experiments reveal the existence of reversible processes that could be related to the bending of the domain walls, which contribute to the dielectric constant of those materials without producing dielectric losses. The dependence of the dielectric constant on the poling state and on ageing are also studied. It can be reasserted that there are two distinct mechanisms that contribute to the dielectric response. The results show that the reversible contribution is independent of the ageing processes suffered by the sample.