Enhanced electric field induced strain in B-site Sb doped BiFeO₃-BaTiO₃ lead free ceramics

Antimony modified 0.67BiFeO₃-0.33BaTiO₃ based ceramics with pure perovskite structure have been fabricated by conventional solid-state reaction method. The effects of single Sb ion doping on the microstructure, permittivity, electric field induced strain (S) and ferroelectric performance are investigated systematically. The XRD and permittivity analysis results indicate a mixed phase of pseudo-cubic and rhombohedral at morphotropic phase boundary (MPB). Compared with other single ion doped BF-BT systems, Sb doped samples show a large strain under relatively small electric field. The highest unipolar strain (0.168%) and converse piezoelectric coefficient d₃₃* (336 pm/V) at 50 kV/cm are obtained in 0.67BiFe_99.75%Sb_0.25%O₃-0.33BaTiO₃ ceramic, Which may be attributed to the domains wall movement facilitated by the soft effect of donor doping Sb. This work suggests simple single B-site ion doping can also effectively improve the electromechanical performance of BiFeO₃-BaTiO₃ based ceramics under low electric field.