The effects of aliovalent cations doping on electric-field-induced strain and microstructures of (Bi0.5Na0.5)0.94Ba0.06TiO3 lead-free piezoceramics

Effects of Al and Nb doped (Bi0.5Na0.5)0.94Ba0.06TiO3(abbreviated as BNB6T) ceramics on dielectric, ferroelectric, and strain properties were investigated. The results indicated that the d33⁎ value is significantly higher in pure BNB6T ceramics than in Nb doped BNB6T and Al doped BNB6T ceramics, and that S–E curve for the Al doped BNB6T ceramics displayed a typical W-shaped butterfly curve, but pure BNB6T and Nb doped BNB6T ceramics display a V-shaped curve. The P–E loops for pure BNB6T and Nb doped BNB6T ceramics were similar to soft PZT ceramics with slim profiles. According to the results of microstructures analysis, significant strain may originate from the development of the optimum compound domains coexistence (the mixture of microdomain and nanodomain), which provide large saturation polarization and low-energy barrier dipole switching under an applied electric field. All these would provide a new concept for lead-free ceramics to realize high strain response for practical applications in actuator or other piezoelectric devices.