Extremely Enhanced Nonlinear Current-Voltage Properties of Tb-Doped CaCu3Ti4O12 Ceramics

Nonlinear current–voltage properties of CaCu3Ti4O12 ceramics were extremely enhanced by doping with Tb. Substitution of Tb to CaCu3Ti4O12 resulted in a decrease in grain size due to the ability of Tb ions to inhibit grain boundary mobility. The dielectric properties of CaCu3Ti4O12 ceramics were degraded after doping with Tb. Surprisingly, the nonlinear electrical properties were strongly enhanced. The best properties with a nonlinear coefficient of ~29.67 and breakdown electric field strength of ~1.52 × 104 V/cm were obtained in the Ca0.775Tb0.15Cu3Ti4O12 ceramic. These extremely enhanced properties were attributed to modification of grain boundary electrical response due to the effect Tb substitution.