In situ Observation of Polarization Reversal of Bi4Ti3O12 with 90° Domain Walls

The in situ observation of polarization reversal of a system with 90° domain wall structures at a low-frequency field was carried out in the c -plate of a ferroelectric Bi 4 Ti 3 O 12 crystal using a polarizing microscope. It was found that there are four kinds of typical modes in polarization reversal with respect to 90° domain walls in ferroelectric materials: the translation of the original 90° domain walls, the pair annihilation of 90° domain walls, the generation of the zigzag-shaped walls, and the translation of 90° domain walls with a box-shaped a -domain. These modes are attributable to two basic processes: the translation and creation/annihilation of 90° domain walls. The polarization reversal with a 90° domain wall structure was discussed on the basis of these four typical modes. It is pointed out that the compatibility of the strain at the wall and the reduction in the depolarization field are the most important principles that govern the polarization reversal of a system with a 90° domain structure.