Ferroelectricity of Bi2SrTa2O9 Single Crystals Grown by the Self-Flux Method

Abstract
Ferroelectric hysteresis of a Bi2SrTa2O9 single crystal, a promising candidate for ferroelectric random access memories (FeRAM), was observed at 200° C. This single crystal, grown by the self-flux method, has a composition characterized as Bi x Sr y Ta2O9 (x=1.91±0.05, y=1.27±0.08). Observing the optical anisotropy of the c-plane, it was found that this material has a Curie temperature (T c) higher than 250° C. Measuring the electrical properties on the c -axis and in the c -plane, it was confirmed that this material has electrical anisotropy. Furthermore, the domain motion of the crystal was observed under an electric field using a high-resolution charge-coupled-device (CCD) microscope system.