Direct determination of the polarization direction of domains in BaTiO3 single crystal

The polarization directions of domains in BaTiO3 single crystal are determined by convergent-beam electron diffraction directly. The intensity distributions in the (001) and (00 (1) over bar) diffraction disks are different, which is due to the noncentrosymmetric unit cell of ferroelectrics. The in situ transmission electron microscopy observations on the evolution of domains under external fields indicate that the disk with a little brighter center fringes is the (001) disk and the polarization vector is toward this disk. The method provides a straightforward criterion for polarization direction determination of ferroelectric domains. (c) 2006 American Institute of Physics.