Switching properties and domain dynamics of the c-axis polarization in monoclinic Bi4Ti3O12 single crystals

抄録

We have investigated the domain structures and their dynamics induced by electric field along the c axis in ferroelectric Bi4Ti3O12 single crystals, taking into account the two spontaneous polarization (Ps) components along the a (Ps(a)) and c axes (Ps(c)). Piezoresponse force microscope observations showed that 90° domain walls (composed of the Ps(a) component) clamp the motion of Ps(c) domain walls, leading to a lower remanent polarization along the c axis. Annealing the crystals under oxidation atmosphere led to not only a complete Ps(c) switching without clamped Ps(c) domains, but also a marked increase in the coercive field for the Ps(c) switching (Ec(c)). The behavior of Ec(c), which cannot be explained by the domain wall pinning attributed to oxygen vacancies, was tentatively interpreted as a result of the interaction between the domain walls composed of Ps(c) and electron hole induced by the oxidation treatment.