Dielectric properties of bismuth layer type ceramics with lanthanum and nickel co-substitutions

The dielectric properties of bismuth-layer-type ceramics with lanthanum and nickel cosubstitutions, Bi₂(Pb_1-xLa _x)(Nb_2-x/3Ni_x/3)O₉ are presented. Above the Curie temperature, the dielectric constant decreases at a rate that can be approximately described by Smolensky´s quadratic law, showing relaxor behavior. At room temperature, the dielectric constant and loss tangent of the new materials are higher than those of the parent Bi₂PbNb₂O₉. High resistivity and breakdown strength make these materials very attractive for applications such as a high-voltage ceramic capacitor dielectric