Low driving field-induced large strain in ternary lead-free Na0.5Bi0.5TiO3-SrTiO3-ABO3 piezoceramics

•Large Smax/Emax (995 pm/V) with an ultralow driving field (2 kV/mm) was achieved.•Na0.5Bi10.5TiO3-SrTiO3-LiNbO3 was synthesized via CFS and MWS methods.•A transition from ferroelectric to ergodic relaxor phase occurs.•Three ternary lead-free Na0.5Bi10.5TiO3-SrTiO3-ABO3 piezoceramics were studied. In this letter, three ternary lead-free Na0.5Bi0.5TiO3-SrTiO3-ABO3 piezoceramics (ABO3 = LiNbO3, BaZrO3, and LaFeO3) were studied. The addition of ABO3 into Na0.5Bi0.5TiO3-SrTiO3 ceramic induces a ferroelectric tetragonal-to-ergodic relaxor pseudocubic phase transition, resulting in the significant disruption of ferroelectric order with the shift of the ferroelectric-relaxor transition temperature down to below room temperature. The conventional furnace sintering and microwave sintering methods are conducted in this study to improve the electric field-induced strain properties of BNST-LN piezoceramic. Interestingly, the Na0.5Bi0.5TiO3-SrTiO3-LiNbO3 sample sintered via microwave sintering method shows an ultrahigh normalized strain of 995 pm/V at an ultralow driving field of 2 kV/mm, suggesting a potential candidate for lead-free piezoactuator applications.