Field-insensitive giant dynamic piezoelectric response and its structural origin in (Ba,Ca)(Ti,Zr)O3 tetragonal-orthorhombic phase-boundary ceramics

BaTiO3 (BT)-based ceramics usually exhibit superior quasi-static piezoelectric response but relatively low electrostrain, which limits their actuator applications. In this study, lead-free (Ba0.835+xCa0.165-x)(Ti0.91Zr0.09)O-3 (x = 0-0.06) (BaxCTZ) ceramics with the compositions close to the tetragonal (T)-rich side of orthorhombic (O)-T polymorphic phase boundary (PPB) were reported to exhibit a field insensitive giant dynamic piezoelectric response (d(33)* >1050 pm/V) over a wide electric field range up to 2 kV/mm, resulting in the large strain value of similar to 0.21 %. Detailed structural investigations combined with various electrical properties measurements reveal that the superior dynamic piezoelectric response is attributed to the combination of piezoelectric effect and domain switching behavior due to the chemical modulated O-T PPB, and the field induced partially irreversible T-O phase transition. The results demonstrate that the studied compositions have great potential for applications of lead-free actuator piezoceramics.