Copper cadmium titanate prepared by different methods: Phase formation, dielectric properties and relaxor behaviors

Giant permittivity was performed in CdCu3Ti4O12 ceramics separately fabricated via the sol-gel technique (SG) and the standard solid-state technique (SS). XRD patterns and Raman spectrums revealed that CdCu3Ti4O12 ceramics with single perovskite-related crystal phase were obtained irrespective of the preparation processing. TG-DSC, XRD, and FT-IR were carried out to explore the formation temperature of crystal phases as well as reaction mechanisms. The results indicated that the phase formation temperature of CdCTO-SG powders is at least 100 °C lower than that of CdCTO-SS powders and the dielectric properties of the CdCTO-SG ceramics are superior to those of the CdCTO-SS ceramics. In addition, three abnormal dielectric peaks were observed in dielectric temperature spectrum regardless of the two methods. Besides, data acquired from impedance and modulus assessments indicated that Maxwell-Wagner polarization contributed to the dielectric responses of samples. Therefore, giant dielectric properties of CdCu3Ti4O12 ceramics conformed to internal barrier layer capacitor (IBLC) effect. Semiconducting grains are closely associated with the presence of mixed valence states of Cu+/Cu2+ and Ti3+/Ti4+ in samples.