Observation of the Impact of Dislocations on Atomic Polarization and Domain Structures in BaTiO3

Abstract

Line defects, dislocations, in ferroelectric materials can facilitate the nucleation of new domains and pin the motion of domain walls, leading to significant electromechanical responses. However, the mechanisms that how dislocations influence surrounding atoms and domains remains unclear. In this study, the influence of mechanically introduced {100}<100> dislocations on atomic polarization and the evolution of domain structures under an applied electric field is examined using aberration-corrected transmission electron microscopy (TEM), paired with solid-state nuclear magnetic resonance and synchrotron X-ray diffraction. The results indicate that dislocations affect the polarization of surrounding atoms and domain pattern depending on the inhomogeneous distribution of dislocations. Additionally, dislocation lines may overlap with or pin domain walls, thereby significantly influencing the evolution of domain structures. Furthermore, in situ electric field TEM experiments provided clear evidence of domain structure changes, demonstrating that dislocations can serve as nucleation sites and anchors for domain walls.