Ultrahigh strain response with fatigue-free behavior in (Bi 0.5 Na 0.5 )TiO 3 -based lead-free piezoelectric ceramics

Abstract In this letter, we report a lead-free piezoelectric ceramic system (Bi 0.5 Na 0.5 ) 1− x Ba x Ti 0.98 (Fe 0.5 Sb 0.5 ) 0.02 O 3 which shows a surprisingly high field-induced nonlinear strain of 0.57% comparable to those obtained in Pb-based antiferroelectrics. The ultrahigh strain response of the composition stems from the composition proximity to the ferroelectric-nonpolar phase boundary, which leads to reversible transformation between a nonpolar phase and a polar ferroelectric phase under cyclic fields. In particular, this material is very attractive for its exceptionally good fatigue resistance (up to 10 6 cycles) and high temperature stability (25–100 °C) due to its stable nonpolar phase and lower defect density. These findings render the current material a great opportunity for novel applications in ultra-large stroke and nonlinear actuators demanding improved cycling and thermal reliabilities.