High strain in (Bi1/2Na1/2)0.935Ba0.065TiO3-Sr3FeNb2O9 lead-free ceramics with giant piezoresponse

The structure, electric field-induced strain (EFIS), polarization and piezoelectric response of lead-free Sr3FeNb2O9-modified (Bi1/2Na1/2)(0.935)Ba0.065TiO3 (BNBT-xSFN, with x = 0-0.012) ceramics were investigated. XRD patterns show that all compositions have a pure perovskite structure and SFN effectively diffused into the BNBT lattice during sintering to form a solid solution. A large EFIS of 0.35% was obtained at the critical composition of x = 0.009 which corresponds to a normalized strain (S-max/E-max) of 583 pm V (1). A maximum value of piezoelectric constant (254 pC N-1) was obtained for x = 0.006. These results show our research can benefit the developments of Bi1/2Na1/2TiO3 ceramics and widen their range of applications.