Some Experiments on the Motion of 180° Domain Walls in BaTiO3

Abstract

Single-crystal BaTi${\mathrm{O}}_3$ samples with aqueous LiCl electrodes in place of the customary noble metal electrodes are observed to undergo polarization reversal with electric fields of several hundreds of volts per cm in a manner very much analogous to certain ferromagnetic materials. It is shown for the first time that polarization reversal in BaTi${\mathrm{O}}_3$ can take place by the expansion of a few domains through extensive sideways 180° domain wall motion. The observed domain configurations show that the smallest switched domains are probably circular in cross section and do not appear to go through the thickness direction of the crystal. The small domains grow through sideways 180° domain wall motion into large ones which have approximately square cross sections with the straight sides at 45° to the $a$ axes. It is also noted that few, and sometimes no, ferroelectric Barkhausen pulses are observed during polarization reversal, and that Barkhausen pulses can occur when two switched domains come together.