Anti-reduction of Ti4+ and improved quality factor in Cu-doped Ca0.61Nd0.26TiO3 ceramics

The occurrence of "dark holes" is a common phenomenon in TiO2-based ceramics, resulting from the reduction of Ti4+ under high-temperature and low-oxygen partial pressure sintering conditions. To achieve low dielectric loss, Ca0.61Nd0.26Ti1-xCuxO3 ceramics were designed and prepared in this work. The results indicate that moderate doping of CuO not only enhances insulation resistivity and Q x f value but also reduces the positive tau f value. The Ca0.61Nd0.26Ti0.98Cu0.02O3 sample exhibited the highest Q x f value of 16,895 GHz, contributing to the miniaturization and insertion loss of microwave devices.