Ultrahigh strain response with fatigue-free behavior in (Bi0.5Na0.5) TiO3-based lead-free piezoelectric ceramics

In this letter, we report a lead-free piezoelectric ceramic system (Bi0.5Na0.5)(1) xBaxTi0.98 (Fe0.5Sb0.5)(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 degrees 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.