Investigation of Structural and Electrical Properties of B-Site Complex Ion (Mg1/3Nb2/3)4+-Modified High-Curie-Temperature BiFeO3-BaTiO3 Ceramics

B-site complex ion (Mg1/3Nb2/3)-modified high-temperature ceramics 0.71BiFeO3-0.29BaTi1−x (Mg1/3Nb2/3) x O3 (BF-BTMNx) have been fabricated by the conventional solid-state reaction method. The compositional dependence of the␣phase structure, electrical properties, and depolarization temperature of the ceramics was studied. The main phase structure of BF-BTMNx ceramics is perovskite phase with pseudocubic symmetry. The experimental results show that the dielectric and piezoelectric properties, and temperature stability strongly depend on the (Mg1/3Nb2/3)4+ content. The optimum (Mg1/3Nb2/3) content enhances the piezoelectric properties, Curie temperature, and depolarization temperature. The ceramic with x = 1% exhibited enhanced electrical properties of d 33 = 158 pC/N and k p = 0.322, combined with high-temperature stability with Curie temperature of T c = 453°C and depolarization temperature of T d = 400°C. These results show that the ceramic with x = 1% is a promising lead-free high-temperature piezoelectric material.