Enhanced intrinsic permittivity and bulk response in Y2/3Cu3Ti4+xO12 ceramics

Considering the contribution of the mixed valence structure of Ti3+ and Ti4+ to the semiconductivity of grain, compositions with the formula of Y2/3Cu3Ti4+xO12 were designed and prepared. The dielectric bulk responses of Y2/3Cu3Ti4+xO12 ceramics were explored in detail. Changing Ti stoichiometry gives rise to an increase of the intrinsic permittivity. Y2/3Cu3Ti3.925O12 ceramic exhibits a higher intrinsic permittivity of ~120 at 60 MHz than that of pure Y2/3Cu3Ti4O12 ceramics (87 at 60 MHz). Additionally, the activation energies of bulk responses are significantly enhanced by changing Ti stoichiometry, which is closely linked with the increase of Ti3+/Ti4+.