Journal Article

Optimized strain performance in -textured Bi0.5Na0.5TiO3-based ceramics with ergodic relaxor state and core—shell microstructure

Zhou, Xuefan, Yang, Huiping, Xue, Guoliang, Luo, Hang, Zhang, Dou

2022

Overview

Herein, a high strain of ∼0.3% with a small hysteresis of 43% is achieved at a low electric field of 4 kV/mm in the highly -textured 0.97(0.76Bi 0.5 Na 0.5 TiO 3 −0.24SrTiO 3 )−0.03NaNbO 3 (BNT−ST−0.03NN) ceramics with an ergodic relaxor (ER) state, leading to a large normalized strain ( d 33 *) of 720 pm/V. The introduction of NN templates into BNT−ST induces the grain orientation growth and enhances the ergodicity. The highly -textured BNT−ST−0.03NN ceramics display a pure ergodic relaxor state with coexisted ferroelectric R 3 ¯ c and antiferroelectric P4bm polar nanoregions (PNRs) on nanoscale. Moreover, due to the incomplete interdiffusion between the NN template and BNT−ST matrix, the textured ceramics present a core-shell structure with the antiferroelectric NN core, and thus the BNT-based matrix owns more R 3 ¯ c PNRs relative to the homogeneous nontextured samples. The high crystallographic texture and more R 3 ¯ c PNRs both facilitate the relaxor-to-ferroelectric transition, leading to the low-field-driven high strain, while the ergodic relaxor state ensures a small hysteresis. Furthermore, the d 33 * value remains high up to 518 pm/V at 100 °C with an ultra-low hysteresis of 6%.

• Publisher: Tsinghua University Press
• Subject: Antiferroelectricity / Bismuth titanate / Ceramics / Characterization and Evaluation of Materials / Chemistry and Materials Science / Composites / Core-shell structure / Crystallography / Electric fields / Ergodic processes / Ferroelectric materials / Glass / Grain orientation / Hysteresis / Interdiffusion / Materials Science / Nanotechnology / Natural Materials / Relaxors / Research Article / Shells / Structural Materials