Antiparallel ferroelectric domains in photorefractive barium titanate and strontium barium niobate observed by high-resolution x-ray diffraction imaging

Abstract

Antiparallel ferroelectric (180-deg) domains have been observed by high-resolution x-ray diffraction imaging in barium titanate and strontium barium niobate. This technique permits the imaging of domains in thick (1-mm) samples with high spatial resolution (1 µm). These domains are visible in both Laue and Bragg geometry but only in those diffraction images for which the diffraction vector has some component along the [001] axis (optical axis). The origin of the domain contrast is explained in terms of the unit cell symmetry and a new coupled-mode view of the dynamical theory of x-ray diffraction. This model also permits determination of domain location relative to the sample surfaces through the analysis of the domain fringe contrast.