Synthesis and characterization of 0.7BiFeO3-0.3BaTiO3 crystallites by the hydrothermal method

BiFeO₃-BaTiO₃ (BF-BT) solid solutions are proved to be a promising candidate for lead-free high-temperature piezoelectric and multiferroic functional materials. In this work, a low-temperature and short-time hydrothermal route was utilized to synthesize BiFeO₃-BaTiO₃ crystallites. The phase evolution was controlled by adjusting the process parameters, such as initial NaOH concentration, reaction temperature and duration time. X-ray diffraction results indicated that pure-phase 0.7BiFeO₃-0.3BaTiO₃ crystallites could be synthesized under the reaction temperature of 200°C for 3 h with NaOH concentration of 10 M. Scanning electron microscopy images showed that the average size of as-prepared powders increased as the extension of duration time. The mechanism of forming BiFeO_3-BaTiO₃ crystallites in the hydrothermal process was investigated and discussed. Moreover, room-temperature magnetic hysteresis curve of the BiFeO₃-BaTiO₃ crystallites revealed weak ferromagnetic property.