X-ray Diffraction Topography of BaTiO3 at Phase Transition Temperature

We performed X-ray diffraction topography analysis on a BaTiO3 single crystal with high-coherence synchrotron X-rays. Since the domain configuration of the BaTiO3 single crystal was unstable and fluctuated with temperature, an excellent temperature control system was used for domain observation. We used a milli-Kelvin (mK)-stabilized cell, which can control BaTiO3 crystal temperature to within +/- 1 mK. By combining the coherent X-rays and the mK-stabilized cell, We detected the domain configuration very sensitively during phase transition. The domain configuration changed markedly at the transition temperature. The low-temperature tetragonal domain fluctuated markedly before the long-range-order structure changed from tetragonal to cubic. The ferroelectric-to-paraelectric transition occurred in two steps; first, the domain configuration changed into a tetragonal phase, and then, the average structure changed into a cubic structure. (C) 2009 The Japan Society of Applied Physics