Influence of B-site complex-ion substitution on the structure and electrical properties in Bi0.5Na0.5TiO3-based lead-free solid solutions

Abstract The influence of B-site complex-ion substitution on the phase transition and dielectric, ferroelectric, piezoelectric properties in (Bi 0.5 Na 0.5 ) 0.93 Ba 0.07 Ti 1 − x (Al 0.5 Nb 0.5 ) x O 3 solid solutions was investigated in detail and a schematic phase diagram was established. The substitution was found to induce a phase transition from the ferroelectric long range order to relaxor pseudocubic phase. A maximum quasi-static piezoelectric coefficient d 33 of 210 pC/N was obtained. Furthermore, at a critical composition x of 0.02, large strain response of ∼0.29% was obtained under ∼5 kV/mm at room temperature with the normalized strain S max / E max as high as 575 pm/V. The high strain behavior was attributed to the field-induced phase transition from ergodic relaxor pseudocubic to ferroelectric phases. The large strain response with good temperature stability would be quite suitable for environmental-friendly solid-state actuator applications.