Enhanced thermal and dielectric properties of CaCu3Ti4O12 by (Fe, La)-co-doping

Abstract

It is found that the linearization of the resistance–temperature curve for CaCu₃Ti₄O₁₂ can be achieved by changing the energy band structure induced by Fe³⁺, but at the cost of decreasing temperature sensitivity. Here, a novel strategy is proposed to improve the thermal and dielectric properties of CaCu₃Ti₄O₁₂ ceramics by (La,Fe)-co-doping. This can both linearize the resistance–temperature relationship by adjusting the energy band structure of the grains due to the Fe³⁺ doping and improve the temperature sensitivity by increasing the grain boundary potential barrier resulting from La³⁺ doping. The dielectric constant increases upon decreasing the grain boundary potential barrier and increasing the carrier concentration. Therefore, the dielectric constant and temperature sensitivity can be regulated by adjusting the characteristics of grains and grain boundary. This work bridges the relationship between thermal sensitivity and dielectric properties, and opens up a door for the development of a multifunctional coupler CaCu₃Ti₄O₁₂ device.