X-ray diffraction topography on a BaTiO3 crystal

We have observed 90deg domain walls in a bulk BaTiO3 crystal by synchrotron radiation topography, coupled with a CCD detector. The BaTiO3 multi-domain crystal was revealed to be strained at the 90deg domain boundary. The polar direction of the BaTiO3 crystal was tilted by this strain, and this strain also causes the irregular angle of the surface bending mode. The synchrotron X-ray topography can be performed on a sample with electrodes. The topographic image of the ferroelectric domain with an electric field clarified that the well-known stripe domain configuration can not be observed without a weak electric field due to the lattice strain at the domain boundary. (author)