Domain evolution processes during poling of a near-morphotropic Pb(Zr, Ti)O₃ ceramic

Domain wall motion during the poling of near-morphotropic Pb(Zr,Ti)O ₃ PZT was observed using Piezoresponse Force Microscopy (PFM). Poling was conducted on bulk polycrystalline PZT in a series of steps, interrupted by vertical PFM scans, which were used to identify the domain evolution processes. The mechanisms of evolution in complex domain patterns such as herringbone and checkerboard structures are revealed. Of interest, in the case of a herringbone pattern consisting of two sets of lamellae angled to each other, one set of lamellae expands and is observed to overwrite the other, transforming the herringbone structure into a single lamination. Also, lengthening without broadening, and simultaneous lengthening and broadening of lamellar domain bands in checkerboard structures are observed. The observations show that 180° and non-180° domain switching can occur simultaneously in complex domain patterns. Methods are developed for identifying the polarization directions of the individual domains in near-morphotropic PZT. The methods combine a knowledge of the compatible domain configurations with crystallographic data from electron backscatter diffraction and PFM data. The resulting map of polarization directions enables clear identification of the polarization switching mechanisms.