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Multistep stochastic mechanism of polarization reversal in orthorhombic ferroelectrics

2021/11/11 by

A stochastic model describing the electromechanical response of ferroelectrics/ferroelastics of orthorhombic structure is developed. A comparison with original experiments on KNN-ceramics threw light on complicated switching scenarios in the material and particularly revealed a significant role of coherent non-180° switching processes (see the figure below) which do not cause spontaneous strain variation.

The theory accounts for all possible parallel and sequential switching events. Application of the model to the simultaneous measurements of polarization and strain kinetics in a lead-free orthorhombic (K, Na)NbO3-based ferroelectric ceramic over a wide timescale of seven orders of magnitude allowed identification of preferable polarization switching paths, fractions of individual switching processes, and their activation fields.