Ferroelectric and dielectric anisotropy in high-quality SrBi2Ta2O9 single crystals

High-quality SrBi2Ta2O9 single crystals were obtained by a self-flux solution method. The crystals were naturally oriented with [001] direction perpendicular to the major face and edges parallel to [110] axes. The dielectric and ferroelectric properties of the crystals were investigated along the c axis and in the ab plane of the orthorhombic unit cell. The ferro-paraelectric phase transition was observed at T-C=355 degreesC. The anisotropy of dielectric permittivity, i.e., the ratio between average permittivity in the ab plane and along c axis was about 10 at T-C and decreased to similar to2 at room temperature. Saturated hysteresis loops were observed for switching in the ab plane. The spontaneous polarization along ferroelectric a axis was estimated to be approximate to20 muC/cm(2). (C) 2004 American Institute of Physics.