Topographic Study on Domain Boundaries in TGS. I

Abstract

Antiparallel domain boundaries in ferroelectric TGS single crystals have been studied by X-ray topography. Systematic observations of the domain boundary contrast on section topographs proved that the contrast depends on the phase of the structure factor of the reflection, but is independent of the absolute value of it. The angular divergence of the diffracted beam from a domain boundary corresponds to that from a perfect region of the crystal. These results exclude the assumption that the cause of the contrast is the strain field around the Bloch type domain walls. An interpretation is given on the analogy of the contrast of a stacking fault in dynamical diffraction theory. The domain boundary contrast is attributed to the phase difference between the structure factors in the two domains at each side of the boundary.