Manganese-Doped BiFeO3-BaTiO3High-Temperature Piezoelectric Ceramics: Phase Structures and Defect Mechanism

The bulk BiFeO3–BaTiO3 system has been studied as a potential lead-free high-temperature piezoelectric material. It is found that the multivalency manganese-doped 0.8BiFeO3–0.2BaTiO3 ceramics exhibit the coexistence of tetragonal and rhombohedral phases, whereas Mn doping improves the resistivity and exhibits hard characteristic. The optimal properties were obtained at 0.12 wt% Mn addition exhibiting Tc ˜ 637°C. The increase of Tc in Mn-modified compositions can be ascribed to the appearance of internal electric bias field by acceptor doping. The combination of good electrical properties and high Tc makes these ceramics suitable for elevated temperature piezoelectric devices.