Domain structure and polarization reversal in ferroelectric lanthanum-modified lead titanate ceramics investigated by piezoresponse force microscopy

In this work, the ferroelectric domain structure of (Pb0.79La0.21)TiO3 transparent ceramics and its response to an applied electric field were investigated by piezoresponse force microscopy (PFM). A qualitative three-dimensional reconstruction of the domains by PFM measurements revealed that the domain structure consists in stripes in two size scales (micro and nanometer) separated by 90° domain walls coexisting with 180° domains. While the nanoscale 90° domains were found arranged in organized structures, (e.g., lamellas, herringbones, and other unusual configurations), the 180° domains form a “labyrinth” structure, typical of ferroelectrics with a degree of disorder. Local application of an electric field reveals different coercive voltages to reorient 180° and the two types of 90° domains and the appearance of a different nanoscale 90° domain structure after poling. While the labyrinth structure is destroyed with relative low voltages, the created 90° domains structure persists, avoiding the formation of a single-domain structure.