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 TiO 2 -based ceramics, resulting from the reduction of Ti 4+ under high-temperature and low-oxygen partial pressure sintering conditions. To achieve low dielectric loss, Ca 0.61 Nd 0.26 Ti 1- x Cu x O 3 ceramics were designed and prepared in this work. The results indicate that moderate doping of CuO not only enhances insulation resistivity and Q  ×  f value but also reduces the positive τ f value. The Ca 0.61 Nd 0.26 Ti 0.98 Cu 0.02 O 3 sample exhibited the highest Q  ×  f value of 16,895 GHz, contributing to the miniaturization and insertion loss of microwave devices.