FERROELASTIC DOMAIN WALLS IN BARIUM TITANATE—QUANTITATIVE PHENOMENOLOGICAL MODEL

ABSTRACT

Properties of ferroelectric domain walls corresponding to rotations of the spontaneous electric polarization by 90 or 180 degrees are investigated in the framework of material-specific generalized Ginzburg-Landau-Devonshire model involving long-range dipole-dipole interactions. Thickness and surface energy for these domain walls in the tetragonal and the orthorhombic phases of BaTiO₃ are evaluated in the charge-free approximation using model parameters determined from independent experiments. Both types of domain walls occur spontaneously in domain pattern simulations, although in the orthorhombic phase the 180-degree domain walls are very rare. The simulated domain patterns and domain wall properties are discussed and the relation to the pronounced anisotropy of the gradient term is pointed out.

Keywords:

• Ferroelectric and ferroelastic domains
• BaTiO₃
• Ginzburg-Landau theory

ACKNOWLEDGMENTS

Helpful discussions with Y. Ishibashi, H. Orihara, E. Salje, A. Tagantsev, V. Janovec and I. Rychetsky are gratefully acknowledged. This work has been supported by the Grant Agency of the Czech Republic (projects 202/05/H003 and 202/06/0411) and by Czech Academy of sciences (project AVCR 1ET300100401).