Donor- and acceptor-cosubstituted BaTiO3 for nonreducible multilayer ceramic capacitors

Donor- and acceptor-cosubstituted BaTiO3 pellets with the composition of [((Ba,Sr)Pbx)0.98La0.02](Ti0.99Mg0.01)O3 are under investigation for the purpose of developing nonreducible dielectric layers for the applications of multilayered ceramic capacitors (MLCCs) with the base-metal electrodes. The added La and Mg in this composition behaved as donors and acceptors, respectively. The Pb addition changed the Curie temperature and grain size. The dielectric performance was dependent upon the Pb content and the re-oxidation treatment. These 1150 °C-annealed pellets demonstrates a satisfying dielectric performance with a grain size of 0.8–1.5 μm, dielectric constant of 48,500, loss tangent of 0.13, TCC of −12% at 85 °C, and leakage current of 9 × 10−9 A at 5 V (∼20 V/cm). The 5% Pb-doped BaTiO3 pellets are most prospective.