Effect of annealing on dielectric behavior and electrical conduction of W~(6+) doped Bi_3TiNbO_9 ceramics

摘要

Bi_3Ti_(1-x)W_x NbO_(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 O_2 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 O_2-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.