Grain orientation effects on the properties of a bismuth layer-structured ferroelectric (BLSF) Bi₃NbTiO₉ solid solution

Bi₃NbTiO₉ ceramics were prepared by ordinary firing and by hot-press sintering. The crystal structures of the ceramics were investigated by X-ray diffractometry. Scanning electron microscopy observation showed that the platelike grains were oriented after hot pressing. Dielectric, piezoelectric, and ferroelectric characterizations, as well as the electrical resistivities, showed remarkable anisotropy in the hot-pressed samples. Because of grain orientation in the hot-pressed samples, the remanent polarization and piezoelectric constant in the direction perpendicular to the pressing axis were much higher than in the unoriented, ordinary fired samples.