Large strain and reduced hysteresis of BiFeO₃-xBaTiO₃ lead-free ceramic via multiphase coexistence and relaxor behaviors

Ferroelectric ceramics with large strain response, low hysteresis and high Curie temperature (T_C) are required for contemporary displacement actuator. In this work, (1-x)BiFeO₃-xBaTiO₃ ceramics were synthesized using traditional solid sintering technique. A high electric field-induced strain (0.25%), a relatively low hysteresis (22.5%) and a high Curie temperature (415 °C) were achieved in BiFeO₃-0.35BaTiO₃ ceramic. Meanwhile, the ceramics exhibited apparent relaxor behavior owing to the local structural heterogeneity. Aberration-corrected scanning transmission electron microscopy revealed that polar nano-regions with multiphase coexistence occur in the material, which is the microstructure origin of the enhanced strain and low hysteresis in BiFeO₃-0.35BaTiO₃ ceramics. This work indicates that BiFeO₃–BaTiO₃-based ceramics are good high-temperature ferroelectric materials and are promising candidates for high-precision actuator.