Quantitative x-ray Bragg diffraction topography of periodicallydomain-inverted LiNbO3

Abstract

Periodic domain inversion in a ferroelectric material (lithium niobate) has been studied using high-resolution x-ray diffraction topography. A domain-inverted structure of period 30 µm was fabricated in a LiNbO3 crystal with a thickness of 300 µm via electric-field poling. The synchrotron-radiation x-ray experiments were carried out at the ESRF micro- fluorescence, imaging and diffraction beamline (ID22). The experimental topograms and numerical simulations show that the image contrast can be explained in terms of a phase shift of the polarizability coefficient, h, in the domain-inverted region relative to the non-inverted part. This phase shift, 1.72, was found to be equivalent to the reflection, 00, from the domain-inverted part of the structure rather than to the reflection, 006, from the non-inverted part. The numerical simulation shows that the width of the transition region between inverted and non-inverted domains (domain walls) is 0.3 µm.