Large electric field-induced strain in ternary Bi0.5Na0.5TiO3-BaTiO3-Sr2MnSbO6 lead-free ceramics

摘要： The large electric-field-induced strain of Bi0.5Na0.5TiO3-BaTiO3 based ceramic make it a potential replacement for lead-based ferroelectrics in actuator applications. Herein, a ternary system (1-x)(Bi0.5Na0.5)0.935Ba0.065TiO3-xSr2MnSbO6 (BNBT6.5-xSMS) ceramic was fabricated using conventional solid-state reaction. It was found that the ferroelectric to relaxor phase transition temperature TF-R gradually shifted to lower temperature by increasing SMS contents. The ferroelectricity and piezoelectricity of BNBT6.5 were highly affected by trace amount of SMS doping. For composition BNBT6.5-0.003SMS, where TF-R was near room temperature, a large electric-field-induced unipolar strain of ~0.4% with high normalized strain (Smax/Emax) of 728 pm/V, which is comparable to lead-based ferroelectric/antiferroelectric ceramics, was achieved owing to the reversible electric-field-induced phase transition between a non-polar relaxor phase to a polar phase with long-range ferroelectric order.