Textured Sr2Nb2O7 ceramics: Microstructure design, high temperature ferroelectric and piezoelectric performance

Sr₂Nb₂O₇ (SNO) ceramics are promising high-temperature piezoelectric materials due to their high Curie temperature (T_C), good thermal stability, and high electrical resistivity. However, SNO presents low piezoelectric activity (d₃₃ < 1 pC/N). Here, we successfully obtain textured SNO ceramics with an orientation factor of 0.86 by microstructure regulation. Saturated polarization-electric loop was obtained in textured ceramic with remanent polarization P_r∼3.56 µC/cm² and coercive field E_C∼53.4 kV/cm. The piezoelectric coefficient d₃₃ of the textured SNO ceramics is increased to 3.2 pC/N, with a high T_C of 1342°C, while the low-textured SNO ceramics exhibit no effective d₃₃. Meanwhile, the piezoelectric coefficient d₃₃ of textured SNO ceramics maintains consistency even at 1300°C, showing excellent thermal stability. The underlying mechanism driving this improvement is elucidated, emphasizing the facilitated domain-wall motion enabled by the engineered microstructure. Furthermore, textured SNO ceramics exhibit high resistivity of 1.33 × 10⁶ Ω⋅cm at 800°C. This study presents a simple and feasible microstructure engineering approach to enhance the piezoelectric properties of layer-structured materials, offering valuable insights into the design and development of ceramics for diverse applications.