Boosting electrostriction and strain performance in bismuth sodium titanate-based ceramics via introducing low tolerance factor chemical modifier

To realize giant electrostriction in BNT-based piezoelectrics, the tuning of thermotropic phase boundary (TF-R) towards ambient temperature is necessary. For the regulation of such TF-R, compositional modification approach either in the form of elemental doping or the substitution of higher tolerance factor ABO3 perovskite is usually preferred. In this study, we used a feasible approach to tune the TF-R of BNT-based system by introducing low tolerance factor ABO3 perovskite to achieve large strain response. To assess our synthetic approach, herein, a novel low tolerance factor perovskite Bi(Zn1/2Ce1/2)O3 is introduced as a chemical modifier and a ternary (0.935-x)Bi1/2Na1/2TiO3-0.065BaTiO3-xBi(Zn1/2,Ce1/2)O3 (BNT-BT-BZC) system is designed and prepared by solid state reaction method. By monitoring the temperature-dependent permittivity and tangent loss, a critical composition is detected for x = 0.015, at which the TF-R tuned down to room temperature (RT). By establishing the relationship between TF-R and electromechanical strain, the composition (x = 0.015) where TF-R situated below RT showed highest strain response (S = 0.43%) accompanied by a giant electrostrictive coefficient Q33 ˜0.036 m4/C2. The derived Q33 value is comparable to the prominent Pb-based counterparts and much higher than the reported lead-free BNT-based electrostrictors. Furthermore, favorable temperature stability in strain and electrostrictive performances is also demonstrated for the BNT-BT-BZC compound. We expect that our current work may provide a highly attractive way for the future development of lead-free electrostrictive materials.