On the Equilibrium Domain Structure of BaTiO3

Plate-like crystals of BaTio3, 20 to 140 µ thick, were treated thermally in order to create conditions for the establishment of an equilibruium 180° domain structure corresponding to minimum electrostatic and wall energy. It has been found that with slow cooling of the crystals from the paraelectric phase in a medium of sufficiently low electric conductivity a c-domain structure near equilibrium is obtained. It is a plate structure with the domain width of 1 to 4 µ. The volumes of “positive” and “negative” domains are equal. The plates are approximately parallel to the crystal-lographical a-axis. The results are qualitatively discussed from the point of view of the kinetics involved in the establishment of the equilibrium domain structure.