Enhanced Insulating and Piezoelectric Properties of Mn-Modified 0.7bifeo3-0.3batio3 Ceramics with High Temperature Stability

BiFeO 3 -BaTiO 3 system has a good application prospect in the field of high temperature lead-free piezoelectric ceramics because of the high Curie temperature and strong piezoelectric characteristics. In this work, the trace Mn 4+ -modified 0.7BiFeO 3 -0.3BaTiO 3 ceramics (0.7BF-0.3BT- x Mn) were fabricated by solid-state reaction method. Mn 4+ doping promoted the formation of rhombohedral phase in the calcined powders. It had only a slight effect on the phase structure of ceramics. With increasing Mn 4+ content, the grain size increased, and a significantly reduced leakage current density was observed in 0.7BF-0.3BT- x Mn ceramics due to the reduced oxygen vacancies, weak transition of Fe 3+ to Fe 2+ and decreased Bi 3+ volatilization. Based on the above, the excellent electric properties ( d 33 =182 pC/N, P r =21.56 μC/cm 2 , k p =0.242) were obtained in 0.7BF-0.3BT-0.003Mn ceramics. In addition, 0.7BF-0.3BT-0.003Mn ceramic exhibited good depolarization temperature and piezoelectric properties of T d =430 o C and d 33 =314 pC/N