Low Temperature Preparation of Bismuth-Related Ferroelectrics by Hydrothermal Synthesis

BIT powder is prepared by hydrothermal synthesis. It is found that the formation of BIT powder is affected by KOH concentration because the XRD intensity increases with increasing the KOH concentration less than 2.0 M. The products are yellowish gray and consist of microscopic lamellar platelets of 0.5 -1.5 mum. Treatment tempereatures are 160 -240 deg C and is decreased with increasing the holding time. The BIT thin films are prepared below 350 deg C by the sol-gel method and hydrothermal treatment for 3 h in Bi(OH)3 0.14 M and KOH 0.01 M mixture solution. The BIT thin film prepared under the optimized condition have hysteresis loops with a good squareness. When 5 V is applied to the BIT film, the polarization at zero electric field is 0.9 muC/cm2 and current density is 8.1x10-6 A/cm2.