Structure, ferroelectric, piezoelectric, and ferromagnetic properties of BiFeO3-BaTiO3-Bi0.5Na0.5TiO3 lead-free multiferroic ceramics

Lead-free multiferroic ceramics of BiFeO3-BaTiO3-Bi0.5Na0.5TiO3 have been prepared by a conventional ceramic technique. The microstructure, multiferroic, and piezoelectric properties of the ceramics have been studied. The ceramics sintered at 1000 degrees C for 2h possess a pure perovskite structure and a morphotropic phase boundary of rhombohedral and tetragonal phases is formed at x=0.02. After the addition of Bi0.5Na0.5TiO3, two dielectric anomalies are observed at high temperatures (T-m similar to 510 degrees C-570 degrees C and T(2 similar to)720 degrees C). The phase transition around T-m becomes wider gradually with increasing x. The ferroelectricity, piezoelectricity, and ferromagnetism of the ceramics are significantly improved after the addition of Bi0.5Na0.5TiO3. High resistivity (similar to 1.3x10(9)cm), strong ferroelectricity (P-r=27.4C/cm(2)), good piezoelectricity (d(33)=140pC/N, k(p)=31.4%), and weak magnetic properties (M-r=0.19emu/g) are observed.