Effect of annealing on dielectric behavior and electrical conduction of W6+ doped Bi3TiNbO9 ceramics

Bi 3 Ti 1 − x W x Nb O 9 + δ (x=0.15) (WBTN-15) ceramics were prepared using the solid state reaction method, and the behaviors of oxygen vacancies were confirmed and investigated by annealing the ceramic samples in O2 and Ar gas atmospheres. Dielectric measurements showed that oxygen vacancies had great contributions to the dielectric loss and constant of Ar-annealed sample, compared with those of as-sintered and O2-annealed samples. dc conductivity measurements indicate that oxygen vacancies played an important role mainly at lower temperature. The WBTN-15 ceramics exhibit intrinsic conduction mechanism at high temperature range and electronic and oxygen-vacancy ionic mixed conduction mechanism at low temperature range.