Direct observation of rotation of polarization at 90-degree domain walls in BaTiO₃

Abstract The rotation of polarization at 90-degree domain walls in tetragonal BaTiO 3 was directly observed by the STEM-CBED method, which combines scanning transmission electron microscopy and convergent-beam diffraction (CBED). CBED patterns wall region exhibit continuous changes intensity distribution within disks specific features corresponding to direction polarization. Simulations were performed using hypothetical superstructures created continuously connecting Ti displacement with a showed good qualitative agreement experimental patterns. quantitative evaluation mirror symmetries existing structure bulk form revealed width is approximately 9 nm. While distorted regions slightly broken symmetry found extend further on both sides 6–7 This finding can explain discrepancy widths reported previous studies.