Investigation on the properties of dielectric and incomplete molecules of nanocrystalline BaTiO3 with cubic perovskite structure

The properties of dielectric and pyroelectric nanocrystalline BaTiO3 powders with cubic perovskite structures were measured. The results show that the grain sizes and structure of the nanocrystalline BaTiO3 materials synthesized by the stearic acid gel (SAG) and sol-gel methods respectively are similar, but the dielectric and pyroelectric properties are different. There is a relaxation phase transition at about 200 K, which indicates that the ferroelectricity exists at lower temperatures in the BaTiO3 nanocrystalline synthesized by the SAG method. The properties are from the incomplete molecules or mesomolecules with various unsaturated coordinations on the nanocrystalline surface and interface.