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.