3D Domain Structure in Bi4Ti3O12 Crystals Observed by Using Piezoresponse Force Microscopy

The 3D domain structure in ferroelectric Bi4Ti3O12 crystals is investigated by using piezoresponse force microscopy. Energetically favorable 90° domain walls with faceted structure are established on the surface along the a–b plane, while the 90° domain walls have complicated and curved surfaces along the c-axis inside the crystals (see figure). This domain structure can be explained by the strong interaction between the 90° domain walls and oxygen vacancies.