A novel strategy to enhance dielectric performance and non-Ohmic properties in Ca2Cu2−xMgxTi4O12

A novel strategy to improve the dielectric and non-Ohmic properties of CaCu3Ti4O12 ceramics that deliberately created a binary-phase system of CaCu3−xMgxTi4O12/CaTiO3 was proposed and can be performed with a starting nominal formula of Ca2Cu2−xMgxTi4O12. Mg2+ doping ions were preferentially incorporated only into the CaCu3Ti4O12 phase. Substitution of Mg2+ into CaCu3Ti4O12/CaTiO3 can cause a significant increase in dielectric permittivity and a large reduction of the loss tangent to <0.015 at 1 kHz; while, retaining excellent temperature dielectric-stability. Sintering time had a slight influence on the dielectric properties, but remarkable effects upon the nonlinear electrical properties of CaCu3−xMgxTi4O12/CaTiO3 ceramics. Degradation of nonlinear properties with increased sintering time is suggested to be the result of the dominant effect of oxygen vacancies. Impedance spectroscopy analysis demonstrated that improved dielectric and nonlinear properties could be attributed to the enhanced electrical responses of CaCu3Ti4O12–CaTiO3 and CaCu3Ti4O12–CaCu3Ti4O12 interfaces resulting from Mg2+ doping ions.