Microstructure and dielectric response of Mg doped Cu3Ti2Ta2O12 ceramics

A series of Cu3−xMgxTi2Ta2O12 (x = 0, 0.05, 0.1, 0.2) ceramics were prepared by a solid-state reaction method, and influences of Mg doping on microstructure and dielectric response were systematically investigated. Mean grain size was enlarged with increasing Mg concentration. An increase in dielectric constant was caused obviously by the substitution of Mg for Cu site. Impedance spectroscopy analyses showed the resistances of grain and grain boundary were decreased by doping with Mg ions. X-ray photoelectron spectroscopy confirmed the presence of Cu+ and Ti3+ ions in the Cu2.95Mg0.05Ti2Ta2O12 ceramic. The active hopping process of charge carriers may be responsible for electrical properties inside the grains. The conduction response and dielectric relaxation behavior were originated by the same electrical mechanism in regardless of temperature, which could be well described using Maxwell–Wagner polarization model.