Electric-field response of polar nanodomains in BaTiO3

In this study, we have investigated the electric-field response of polar nanodomains in the ferroelectric tetragonal phase of BaTiO3. Polar nanodomains were observed by a combination of scanning transmission electron microscopy (STEM) and convergent-beam electron diffraction (CBED). By applying an electric-field, significant changes in the distributions of nanometer-size domains were observed, besides the changes in the configurations of mesoscopic 90° and 180° ferroelectric domains. The obtained CBED patterns are categorized into three. One has higher tetragonal symmetry, and the other two show a deviation from tetragonal symmetry and exhibit a left-right reversal relation with each other. We propose a structural model of the rhombohedral nanodomain redistribution to reproduce the observed CBED patterns. The model consists of a balanced change in volume and size of rhombohedral nanodomains.