Specific features of structure and ferroelectric properties of BaTiO3 phases

Analysis of the interatomic Ti-O distances in the asymmetric Ti-O⋯Ti bridges in the ferroelectric barium titanate phases showed that the rhombohedral, orthorhombic, and tetragonal BaTiO3 phases consist of TiO32−, TiO2, and TiO2+ groups, respectively. The groups show strong electrostatic interaction and, so, orient along one direction, which gives rise to spontaneous polarization of these phases. In each phase, polarization switching under the action of a rather strong electric field proceeds via transfer of the oxygen atoms from one titanium atom to another with simultaneous change of the group orientation to the opposite one.