Abstract
Several hard X-ray imaging techniques greatly benefit from the coherence of the beams delivered by modern synchrotron radiation sources. This is illustrated with examples with ferroelectric materials on BL47XU, an undulator beamline at SPring-8. There is two types of ferroelectric domains in barium titanate (BaTiO_3) at room temperature tetragonal phase; one is 90°- and another is 180°-domain configurations. Around the ferroelectric domain boundary, a large strain exists to compensate for different lattice parameters. In 90°-domain configuration, the strain is equal to a simple type planar defect, that affects the ferroelectric properties seriously. The topographic image of the ferroelectric domain boundary will give much information about strain transmission process, and micro-domain induced structure like domain-engineering ferroelectric materials. By combining the optical microscope and X-ray topography, the lattice-strained region at domain boundary was observed and the mechanism of lattice-strain relaxation was understood. In the pure BaTiO_3 single-crystal with large ferroelectric domains, the size of lattice-strained area was of μm order.
