Lead-free Ba_0.98Ca_0.02Zr_0.02Ti_0.98O₃ceramics with enhanced electrical performance by modifying MnO₂doping content and sintering temperature

Lead-free Ba_0.98Ca_0.02Zr_0.02Ti_0.98O₃-xmol% MnO₂(BCZT-xMn) (x = 0.1, 0.2, 0.3, 0.4, 0.5) ceramics were prepared by conventional solid-state reaction method and the effects of MnO₂doping content and sintering temperature on microstructure and electrical properties of BCZT ceramics were studied. The ceramics samples with all MnO₂doping contents exhibit pure perovskite structure and similar Curie temperature of approximately 120 °C. Among all, the sample with 0.3 mol. % MnO₂doping content sintered at 1400 °C exhibits improved ferroelectricity with a relatively high remnant polarization (P_r) and low coercive electric field (E_c) of 15.7 μC/cm²and 180 V/mm, respectively, which can be attributed to the fact that an appropriate doping content of MnO₂does favor to the grain growth, with the favorable effect on domain motion. Accordingly, excellent piezoelectric property with piezoelectric coefficient (d₃₃) of 308 pC/N can be obtained. Besides, the sample shows a relatively low dielectric loss (tanδ) of 1.04%. As a result, the BCZT-xMn ceramic exhibits the potential to be used in memory and transformer applications.