High thermal sensitivity and dielectric constants in CaCu3Ti4O12-LaMn1-xFexO3 composite ceramics by designing sandwich and core-shell structure

In this work, a series of CaCu₃Ti₄O₁₂-LaMn_1-xFe_xO₃ sandwich and core-shell structured ceramics were prepared by using the conventional solid-state method. For these structures, LaMn_1-xFe_xO₃ is encapsulated by the CaCu₃Ti₄O₁₂ (CCTO) layer as a core and interlayer. These ceramics demonstrate high sensitivity with material constants (B) ranging from 7391 to 9786 K and temperature coefficients up to −7.03 %. In addition, Fe³⁺ doping optimizes the electronic structure of LaMnO₃ (LMO) and enhances the Jahn-Taylor coupling and charge localization, thus leading to an increase in the material constant. Furthermore, the core-shell ceramics of CCTO-LMO (Co-LMO) have a high dielectric constant of 16731 at 1 kHz, which exceeds that of the CCTO samples. This enhancement can be attributed to the increase in potential differences caused by the additional carriers. The proposed schemes in this work have important implications for regulating the thermal sensitivity and permittivity of CCTO-based multifunctional coupled electronics.