Preparation of nm-sized barium titanate fine particles and their powder dielectric properties

Barium titanate (BaTiO3) crystallites with various particle sizes from 17 to 100nm were prepared by the 2-step thermal decomposition method of barium titanyl oxalate (BaTiO(C2O4)(2)-4H(2)O). The crystal structure of these BaTiO3 particles was assigned to cubic m-3m by a X-ray diffraction (XRD) measurement while it was assigned to tetragonal 4mm by a Raman scattering measurement. Investigation of impurity in these particles using both TG-DTA and FIF-IR measurements revealed that no impurity was detected in the BaTiO3 lattice while hydroxyl and carbonate groups were detected only on the surface. The dielectric constants of these powders were measured using suspensions by a modified powder dielectric measurement method. As a result, the dielectric constant of B aTiO(3) particles with a size of around 70nm exhibited a maximum of over 15,000. This study revealed that BaTiO3 particles with a size around 70nm were the most desirable for capacitor application.