Size effect on the dielectric properties of BaTiO3

Abstract

BaTiO3 ultrafine particles of different size were prepared by Sol-Gel process. Their microstructure was examined at room temperature. The temperature dependence of the dielectric properties of the pressed pellets and fired ceramics of these particles was studied. With the decrease of particle size d, the Curie temperature decreases while the tetragonal-orthorhombic and orthorhombic-trigonal phase transition temperature increase, and the three dielectric peak become lower and broader and eventually disappear in the following sequence: trigonal-orthorhombic, orthorhombic-tetragonal, tetragonal-cubic. The critical size at which ferroelectricity disappears was determined by dielectric measurement, which agrees with that determined by XRD technique.