Giant strain response in 2 mol% Nb-doped (Bi0.5Na0.4K0.1)TiO3 lead-free ceramics
2017
Wang, Cheng | Xia, Tiandong | Lou, Xiaojie | Tian, Shutao
A series of Nb-doped (Bi₀.₅Na₀.₄K₀.₁)TiO₃ lead-free piezoelectric ceramics were fabricated by a conventional solid-state reaction method. The X-ray diffraction patterns reveal a pure perovskite structure for all the samples. A giant strain of 0.34% is achieved at 2 mol% Nb-doping concentration, and the corresponding normalized strain [Formula: see text] reaches 625 pm V⁻¹, which is one of the best results of the BNT-based ceramics. Complex ac impedance data indicate that only the bulk effect contributes to the resistivity. The compositionally induced disruption of long-range ferroelectric order and relaxor transition contributed to the pinched polarization loops as well as the large electric field-induced strain. The results indicate that appropriate Nb-dopant content can remarkably enhance the strain level of (Bi₀.₅Na₀.₄K₀.₁)TiO₃ ceramics, making it a promising candidate for actuator applications.
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