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

Abstract

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, Ca_0.61Nd_0.26Ti_1-xCu_xO₃ 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_0.61Nd_0.26Ti_0.98Cu_0.02O₃ sample exhibited the highest Q × f value of 16,895 GHz, contributing to the miniaturization and insertion loss of microwave devices.