Electric and optical properties of the 90° ferroelectric domain wall in tetragonal barium titanate

Abstract

The electric and optical properties within 90 • ferroelectric domain walls of tetragonal barium titanate (BaTiO 3) are theoretically examined at room temperature using a microscopic model which is based on the orbital approximation in correlation with the dipole-dipole interaction. We find that when perpendicularly crossing the domain wall,the variation of the spontaneous polarization and refractive indices does not depend on the thickness of the domain wall which varies between 1.5 and 2.5 nm. Moreover, within the domain wall, the refractive indices n 2 and n 3 , corresponding to light polarized parallel to the principal axes y p and z p , respectively, exhibit an important transition in which n 2 transforms from the ordinary to the extraordinary state, while n 3 behaves oppositely to n 2 .

Ferroelectric thin films: Review of materials, properties, and applications

“…• Third, the local anisotropy in ferroelectrics arises equally from both the birefringence between differently oriented domains 349 and from local strain either at domain walls or between the substrate and the FE material. 350 Note that beyond ferroelastic domain walls 351 also 180°domain walls in FEs ͑Refs. 352 and 353͒ give rise to appreciable optical contrast effects that are of importance to be probed locally.…”