Clamping of Non-180° Domain Walls in Bi-Based Ferroelectric Single Crystals

抄録

We have investigated the behaviors of domain clamping in Bi-based ferroelectric single crystals of Bi₄Ti₃O₁₂ (BiT) and (Bi_0.5Na_0.5)TiO₃ (BNT) using piezoresponse force microscopy (PFM). PFM observations reveal that 90° domains are clamped during polarization switching in BiT single crystals. BNT single crystals exhibited a large volume fraction of unswitched 71° domains after applying a high electric field. Electrostatic potential calculations for 90° domain structure indicate that the most stable sites for oxygen vacancies are adjacent to the domain walls with a distance of 0.1 nm. These experimental results and calculations show that an attractive interaction between non-180° domain walls and oxygen vacancies is the main origin of the clamping of non-180° domains in Bi-based ferroelectrics.