Influence of thermal and electrical histories on domain structure and polarization switching in potassium-modified lead zirconate titanate ceramics

The dependence of domain evolution and polarization switching on thermal and electrical histories has been investigated for K1+-ion-modified lead zirconate titanate (PZT) ceramics by using hot-stage transmission electron microscopy and Saywer-Tower polarization methods. In each case, the domains were very narrow, on the order of several hundred angstroms, In the aged condition, the domain structure was dominated by a "wavy" morphology. In the as-quenched condition, fine and straight 180 degrees domains were found that extended across entire grains. In the field-cooled condition, fine and straight 70 degrees and 110 degrees domains were found, Corresponding polarization studies revealed double-loop characteristics in the as-quenched and aged conditions. In both these cases, the switchable polarization was much less than that of the base PZT composition, In the field-cooled condition, a single polarization loop was observed. However, the polarization-electric field (P-E) curve was skewed from the origin, and the polarization was not completely switchable on field reversal. These changes in domain stability and P-E properties have then been explained in terms of the dependence of a spatial distribution of polarizable defect complexes on thermal and electrical histories.