High-temperatre X-ray diffraction study of BiWO

Yoneda, Yasuhiro   ; Kohara, Shinji*; Han, J. S.*; Takeda, Hiroaki*; Tsurumi, Takaaki*

BiWO of a bismuth layered compound is expected as non-lead system ferroelectric. The Curie point is in about 1000C. Therefore, it was thought that it became possible to synthesize below the Curie point, and the sample of a single domain was obtained easily in crystal breeding by the flux method and the thin film making by the PLD method. However, a lot of observations not thought about were found with a single domain as for the BiWO crystal actually made. Then, it is a purpose of this experiment to perform high-temperature X-ray diffraction of BiWO, and to verify the phase transition system again. As a result of the experiment, it has been understood that additional structural phase transition exists also below the Curie point. The domain configuration changes by the existence of another phase transition caused during cooling afterwards even if the crystal is promoted below the Curie point at the high temperature.