Preparation of Ferroelectric BaTiO₃ Films by Sol-Gel Process and Dielectric Properties

Abstract

Crack-free and dense BaTiO₃ films with perovskite structure were obtained at temperature as low as 500°C by the sol-gel process. Barium acetate and tetra-n-butyl orthotitanate were used as raw materials. Glycerol and methanol were used as solvents. The films were deposited on several types of substrates. ICP analysis showed that the Ba/Ti ratio in BaTiO₃ films agreed with that of starting mixtures. Films obtained at 1000°C on a platinum substrate showed a typical P-E hysteresis loop. The spontaneous polarization was 2.3μC⋅cm^-2, the remanent polarization was 0.8μC⋅cm^-2 and the coercive filed was 2.8kV⋅cm^-1. Dielectric constant and dielectric loss angle were about 1000 and 0.035, respectively.