Giant field-induced strain in Nb 2 O 5 -modified (Bi 0.5 Na 0.5 ) 0.94 Ba 0.06 TiO 3 lead-free ceramics

Abstract Lead-free piezoceramics (Na (1+ x )/2 Bi (1- x )/2 ) 0.94 Ba 0.06 Ti 1- x Nb x O 3 (BTN100 x ) were prepared using conventional solid-state reaction method. The structures, field- induced strain, AC impedance of sintered ceramics were investigated. The pure perovskite solid solution BTN3 exhibited giant electric-field-induced strain of 0.478% under an electric field of 70 kV/cm at ambient temperature, meanwhile, the normalized strain ( S max / E max ) reached up to 654 pm/V. The giant strain was insensitive to temperature and exhibited excellent fatigue resistance performance within 10 6 switching cycles, making it a promising candidate material for actuator applications. Complex AC impedance spectra confirmed the contribution of grain effect to resistivity behavior. The field-induced giant strain was attributed to the phase transition between ferroelectrics and relaxor ferroelectrics induced by introducing Nb 2 O 5 .