Preparation and properties of crystals of barium titanate, BaTiO₃

A technique is described for the preparation of `single' crystals of BaTiO₃. At room temperature the crystals are complexes of habit appropriate to cubic symmetry, but consisting of multiply-twinned tetragonal components with orientation very sensitive to externally applied pressure or electric fields. Optical and X-ray observations have been used in a detailed study of the nature of the transitions occurring near 120° C., near 0° C., and near -90° C.