Modeling polarization switching response of ferroelectric ceramics based on multiple natural configuration theory

Ferroelectric ceramics experience polarization switching, which is macroscopically shown by nonlinear hysteretic responses when subjected to high compressive stresses and/or high amplitude of the electric field. We model the nonlinear hysteretic response of ferroelectric ceramics by considering evolutions of microstructural changes associated with changes in the dipole orientations due to both electrical and mechanical stimuli. We adopt the theory of multiple natural configurations, associated with multiple stress-free and electric-field-free states, in incorporating the effect of microstructural changes on describing the nonlinear electro-mechanical hysteretic response of ferroelectric ceramics. The first stress-free and electric-field-free states are associated with the original microstructure of the materials, in which the dipoles in the ferroelectric ceramics are randomly oriented. The new configurations are formed when the ferroelectric ceramics are subjected to relatively large stimuli, which align the dipole orientations. As each configuration is associated with a specific microstructure (a state of dipole orientations), mechanical and electrical properties characterized at different configurations will be different. To examine the model, experimental data on PZT (lead zirconate titanate) ceramics under electric and stress fields, available in the literature, are used. The model is capable of describing the hysteretic response in PZT under electro-mechanical stimuli.