Anisotropy of speckle-field in barium-sodium niobate crystals

The dependence of the speckle-field in Ba/sub 2/NaNb/sub 5/O/sub 15/ crystals in laser beam on the orientation of the crystals, temperature and direction of growing was investigated. The different pattern of scattering along the a and c axis make it possible to unambiguously determine the direction of the ferroelectric axis in the crystal, while abrupt change in the nature of scattering with a ferroelectric phase transition makes it possible to determine the Curie point.