Phase transition of ferroelectric (Na/sub 1/2/Bi/sub 1/2/)TiO/sub 3/

Crystals of (Na/sub 1/2/Bi/sub 1/2/)TiO/sub 3/ were grown by flux technique as well as Czochralski method. It has been found that non-stoichiometry which was induced during the crystal growth by the Czochralski method owing to the volatilization of the Bi-rich phase resulted in less lattice distortion from cubic symmetry. A long-range cationic ordering was also found in both crystals but the degree of ordering was very low. It was confirmed that the tetragonal phase should be nonpolar. On the base of these results, the phase transition behaviors of two NBT crystals have been investigated with the observation of twin configuration.