Effects of La Doping on the Structural and Dielectric Properties of Barium Titanate Ceramics

Abstract

Polycrystalline samples of Ba1-xLaxTiO3 (x = 0.0, 0.002, 0.004) were prepared by a standard high-temperature solid-state reaction method. XRD studies confirmed the formation of a polycrystalline compound with a tetragonal crystal structure. SEM images suggested the presence of a polycrystalline microstructure with certain degree of porosity, and the grains appeared to be distributed inhomogeneously throughout the pallet samples. Dielectric studies indicated a ferroelectric–paraelectric phase transition with a clear shift in the Curie temperature (Tc) of BaTiO3 towards a lower temperature upon doping. The brick-layer model was used to study the potential barrier and the structure of the grain-boundary region of the Ba9.998La0.002TiO3 and Ba9.996La0.004TiO3 ceramics. These ceramics exhibited good density and a homogeneous distribution of the grains. The thickness of the grain-boundary region was calculated to be approximately 200 nm.