WHITE-BEAM X-RAY TOPOGRAPHY STUDY OF KTa1-xNbxO3 CRYSTAL WITH SYNCHROTRON RADIATION

The photorefractive Fe-dopoed KTa 1-x Nb x O 3 (KTN) with a Curie point near room temperature has been topographically studied by Beijing synchrotron radiation white-beam X-ray source. Besides inclusions and the [010] oriented growth bands present in KTN, a set of domains perpendicular to the growth bands is shown, the latter is found to disobey the vanishing rule of planar defects, and to be revealed only by X-ray anomalous scattering. A striking wavelength dependence of the domain contrast is shown by tuning the synchrotron radiation, and the contrast reversal of the domains is demonstrated in antiparallel reflections. The domains are ascertained to be 1800 ones. The origins of formation of the domains and the growth features in KTN are outlined.