Experimental and theoretical investigation on polarization reversal in unfatigued lead-zirconate-titanate ceramic

The dynamics of polarization switching in a soft lead-zirconate-titanate ceramic has been studied over a broad time window ranging from 10−6–106 for applied fields between 0.5 and 2.5 kV/mm. The classical Kolmogorov–Avrami–Ishibashi model of the polarization reversal was not able to satisfactory explain the obtained results. Therefore, a new concept for the polarization dynamics of ferroelectric ceramics has been suggested, which is based on two principal assumptions, (1) a strong dependence of the polarization switching time on the local electric field and (2) a random distribution of the local switching times caused by an intrinsic randomness in the field distribution within the system. Thereby the switching volume is composed as an ensemble of many regions with independent dynamics governed by local field exclusively. Such random field distribution could be well adjusted by a Gaussian distribution around the mean value of the field applied. A total polarization dependence on time and applied field was obtained in explicit form with only three fitting parameters which enabled a good description of the experimental results on polarization reversal in the whole time-field domain.