Journal of the American Ceramic Society, Vol.95, No.5, 1619-1627, 2012
Modeling 180 degrees Domain Switching Population Dynamics in Polycrystalline Ferroelectrics
The macroscopic hysteretic response associated to the underlying microscopic 180 degrees switching of domains in a polycrystalline ferroelectric system is investigated for bipolar, sesquipolar, and unipolar electrical loadings. As a result of the intergranular interactions and physical electromechanical couplings, three polarization populations are found and summarized as the linear superposition of four Gaussian polarization distributions. These distributions quantify the simple switching, the negative switching, and the domain-pinning mechanisms. The reconfiguration of the local polarization and hydrostatic stress distribution indicates that the polarization domains and stress fields are correlated during ferroelectric domain switching. Results show that in the sesquipolar regime, tensile stresses are minimized by 33% and compressive stress minimized by 38%. The maximum strain output decreases by only 1%, thus favoring favoring fatigue-reduced actuation microstructures.