BaTiO3/Bi_(0.5)Na_(0.5)TiO3 Interface Responsible for Anomalous Piezoelectric and Ferroelectric Behavior

摘要

Ferroelectric materials are commonly used in sensor, actuator, and transducer technologies due to their unique ability to couple electrical and mechanical-energy transformations. In recent years, lead-free piezoelectric materials have drawn extensive attentions due to being eco-friendly. Up to now, the lead-free piezoelectric materials are competitive for some specific properties but still not good enough to achieve the replacement of lead-based one, e. g., the BaTiO3 (BT) has exhibited a much higher piezoelectric response (d33) than the commercialized PZT, while its low Curie temperature (Tc = 120 °C) still restrains the application range. To solve the problem, the strain engineering has been employed to 2D [1] ferroelectric materials to improve theTcbyusingthe lattice mismatchbetweenthe thinfilmand itssubstrate withdifferent lattice constants, which causes 2D heteroepitaxial interface. In that case, the Tc of BT has been inconceivably increased toover540°C, whiletheimprovement onthed33 has not yetbeenreported.Inthecaseofthebulkferroelectric materials [2] with 3D heteroepitaxial interface, even the strain engineering has been rarely employed. To fulfill both the improved d33 and Tc of the bulk ferroelectric materials, we have successfully synthesized mesocrystalline BaTiO3/Bi_(0.5)Na_(0.5)TiO3 (BT/BNT) nanocomposites by introducing the strain engineering with 3D heteroepitaxial interface. [3]