Ferroelectric domain structure and c-axis polarization switching in monoclinic Bi4Ti3O12 single crystals

Using a piezoresponse force microscope, the authors have investigated the domain structure and the c-axis domain switching taking the spontaneous polarization (P-s) components of the a axis (P-s(a)) and the c axis (P-s(c)) into account in monoclinic Bi4Ti3O12 single crystals. 90 degrees domain walls composed of the P-s(a) component are shown to impede the switching of the P-s(c) domains, leading to a lower remanent polarization along the c axis. The oxidation treatment of the crystals led to a marked increase in the coercive field for the P-s(c) switching, which cannot be explained by the domain wall pinning attributed to oxygen vacancies. (C) 2007 American Institute of Physics.