Domain wall excitations and their contributions to the weak-signal response of doped lead zirconate titanate ceramics

The ac field dependence of the polarization and strain responses of three different compositions of doped lead zirconate titanate ceramics were measured for samples in both the poled and the depoled states. The results indicate that a reversible domain wall excitation exists which contributes to the weak-signal response of these materials. Irreversible domain wall motion can be excited within the frequency range measured by applying a field above a threshold field, which is much smaller than the coercive field. Therefore, the weak-signal linear dielectric, piezoelectric, and elastic coefficients of these materials may not provide a suitable description of their behavior when the external applied field exceeds this threshold field. All the observed phenomena can be explained by thermally activated domain wall fluctuations and nucleations.