GROWTH OF LARGE PBTIO3 CRYSTALS BY A SELF-FLUX TECHNIQUE

Pure lead titanate (PbTiO3) crystals (5 X 5 X 5 mm3) were grown from high-temperature solutions by a slow cooling technique using PbO as a self-flux. The optimum growth conditions were determined to be: (1)(1-x) TiO2 + X PbO with x (in mol%) varying from 0.78 to 0.82 for the starting compositions, (2) 930-1050-degrees-C as the growth temperature range and (3) 0.4-1.5-degrees-C/h as the cooling rates. Evaporation of PbO was significantly reduced by use of a double-crucible technique. The grown crystals were characterized by X-ray diffraction, chemical analysis and optical microscopy. The transformation temperatures (onset) of 492.5-degrees-C (on heating) and 491.3-degrees-C (on cooling) were determined by differential scanning calorimetry. The transformation process had a thermal hysteresis of 1.2-degrees-C from onset data.