Dielectric properties of Ba_0.5Sr_0.5TiO₃ ceramics sintered by pulse electric current sintering

Cu²⁺, La³⁺ and (Cu²⁺, La³⁺) co-doped BST ceramics were fabricated from the powder prepared by using barium nitrate, strontium nitrate, copper nitrate, lanthanum nitrate, tetra-n-butyl titanate, and ammonium hydroxide via a citrate-nitrate combustion process. Pulse electric current sintering (PECS) was carried out to obtain the compact crystalline BST. The effects of Cu²⁺, La³⁺ doping and(Cu²⁺, La³⁺) co-doping on the dielectric property of BST were investigated. It showed that Cu²⁺, La³⁺ doping and (Cu²⁺, La³⁺) co-doping in BST bulk could dramatically modify the homogeneous of grain sizes in the sintered samples. The dielectric test showed that the Cu doping decreased not only loss tangent, but also the dielectric constant, while La doping and (La, Cu) co-doping decreased the loss tangent, but increased the dielectric constant at 25°C to some degree.