Thermal Evolutions of the Domain Walls in a BaTiO3 Nanoparticle

Abstract

Direct observations of domain walls by using transmission electron microscope were applied to BaTiO3 (BT) nanoparticles synthesized by using the solvothermal reaction method. Many BT nanoparticles with domains were observed, and the domain walls were 2-4 nm in width and appeared to be parallel to the (111) planes. The thermal evolutions of the domain walls of the about 25-nmsized BT particle were confirmed by using in-situ high voltage electron microscopy at temperatures from RT to 200 C. The (110) and (001)/(002) planes appeared in the domains, and the domain walls with a 3-nm width were parallel to the (111) plane. As the temperature increased, the area of the domains increased, and the domain walls became narrower. The domain walls re-widened at the same position and the same area when cooled down to room temperature.