Solvothermal synthesis and Curie temperature of monodispersed barium titanate nanoparticles

Barium titanate (BaTiO₃) nanoparticles with various particle sizes were prepared by a solvothermal method. X-ray powder diffraction (XRPD) patterns show that the as-prepared powders are of pure perovskite BaTiO ₃. Scanning electron microscopy (SEM) reveals that all the particles of BaTiO₃ with different sizes are dispersed homogenously and have uniform size. The room temperature and in situ high temperature XRD analyses indicate that both the proportion of the tetragonal phase and the Curie temperature of BaTiO₃ increase with increasing particles size. The effects of the reaction parameters, such as the concentration of reactants, the polarity of solvent, the reaction temperature and the amount of surfactant, on the size, morphology and uniformity of BaTiO₃ nanoparticles are studied in detail.