Fabrication and characterization of CdCu3Ti4O12 ceramics with colossal permittivity and low dielectric loss

•CdCu3Ti4O12 (CdCTO) ceramics were fabricated via the sol-gel technique.•A giant permittivity and low loss tangent: εr ≈ 6.0 × 104 and tan δ = 0.056 (1 kHz) could be obtained in CdCTO ceramics sintered at 1000 °C. The dielectric constant is about 145 times higher than that reported by M.A. Subramanian et al. in 2002.•The giant permittivity of CdCTO ceramics was attributed to internal barrier layer capacitor (IBLC) theory.•X-ray photoelectron spectroscopy (XPS) indicated mixed valence states of Cu+/Cu2+ and Ti3+/Ti4+ of the sample.

CdCu3Ti4O12 (CdCTO) ceramics were fabricated using a sol-gel technique, which performed an unconventional giant permittivity (GP) and low dielectric loss: εr ≈ 6.0 × 104 and tan δ = 0.056 (at 1 kHz). The abnormal dielectric peaks could be ascribed to the contribution of doubly-ionized oxygen vacancies at high temperature range. In addition, the GP phenomenon of CdCTO ceramics were attributed to the internal barrier layer capacitor (IBLC) theory. The results of X-ray photoelectron spectroscopy (XPS) indicated the mixed valence states of Cu+/Cu2+ and Ti3+/Ti4+ of samples.