@article{Butnoi2026, 
author = {Pichitchai Butnoi and Supalak Manotham and Kamonporn Saenkam and Waraporn Boontakam and Chatchai Kruea-In and Thapanee Srichumpong and Kamonpan Pengpat and Chamnan Randorn and Thanatep Phatungthane and Gobwute Rujijanagul},
title = {Breaking the strain–symmetry trade-off via electrostriction-mediated reversible phase transition in B-site-engineered BNKT-based ceramics},
year = {2026},
journal = {Journal of Advanced Ceramics},
keywords = {bismuth sodium potassium titanate (BNKT), giant strain, large electrostrictive coefficient, lead-free ceramics, biomaterials, bioactivity},
url = {https://www.sciopen.com/article/10.26599/JAC.2026.9221335},
doi = {10.26599/JAC.2026.9221335},
abstract = {Achieving large electrostrain together with a symmetric bipolar response remains challenging in lead-free piezoceramics, as mechanisms that generate large strain often involve irreversible polarization processes that limit strain reversibility. Here, B-site Zr engineering in Bi0.495La0.005Na0.400K0.100Ti1−xZrxO3 (x = 0.000–0.025) enables a large electrostrain (~0.52%) together with a nearly symmetric bipolar strain–electric field (S–E) response. The optimized composition (x = 0.015) exhibits a large normalized strain coefficient (d*33 ≈ 867 pm/V), while x = 0.025 shows an enhanced electrostrictive coefficient (~0.055 m4/C2), indicating strengthened electrostriction-dominated behavior. The enhanced electromechanical response originates from Zr-induced lattice softening and R3c–P4bm phase coexistence, which flatten the free-energy landscape and promote reversible field-driven polarization dynamics. The reduced remanent polarization and coercive field suppress irreversible domain-wall motion, thereby favoring electrostriction-governed strain generation. These results demonstrate that coupling lattice softening with phase coexistence provides an effective design pathway for achieving large, nearly symmetric bipolar strain through electrostriction-dominated mechanisms in lead-free piezoceramics.}
}