A link between p-type electrical conduction and microwave dielectric loss in highly ordered Ba(Co1/3Nb2/3)O3 ceramics

BaCo1/3Nb2/3O3 ceramics, with a high density and a similar, high degree of 1:2 B-site cation ordering, exhibit very different quality factors, Q. The ceramics exhibit p-type behavior with higher conductivity and lower Q for samples processed in O2 as compared with those processed in air. It is proposed that unavoidable Co loss during high-temperature ceramic processing leads to p-type doping that must be compensated by oxygen vacancies to impede hole formation. The composition exhibiting only intrinsic conduction and optimized Q is not achieved with processing in atmospheric oxygen due to filling of oxygen vacancies and hole formation during cooling.