Contrast reversal of antiparallel domains in Cu-doped (Ba0.25Sr0.75)0.9(K0.5Na0.5)0.2Nb2O6 single crystal with synchrotron topography

Abstract

Synchrotron-radiation topographic observations have shown that the Cu-doped (Ba0.25Sr0.75)0.9(K0.5Na0.5)0.2Nb2O6 crystal has a strong ferroelectric x-ray anomalous-scattering effect at the wavelength near the absorption edge of Ba atoms. The reversal of anomalous contrast of antiparallel domains in the crystal was directly revealed in the topographs of hkl and hkl̄ reflections. It was found that the domain walls are all polar and are formed to compensate the charges resulting from the inhomogeneous distributions of the metal atoms in the bulk crystal.