Achieving giant electrostrain of above 1% in (Bi,Na)TiO<sub>3</sub>-based lead-free piezoelectrics via introducing oxygen-defect composition.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36735779.
- Also identified by DOI 10.1126/sciadv.ade7078 and PMC identifier 9897659.
- Licence recorded as CC BY-NC.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Piezoelectric ceramics have been extensively used in actuators, where the magnitude of electrostrain is key indicator for large-stroke actuation applications. Here, we propose an innovative strategy based on defect chemistry to form a defect-engineered morphotropic phase boundary and achieve a giant strain of 1.12% in lead-free Bi<sub>0.5</sub>Na<sub>0.5</sub>TiO<sub>3</sub> (BNT)-based ceramics. The incorporation of the hypothetical perovskite BaAlO<sub>2.5</sub> with nominal oxygen defect into BNT will form strongly polarized directional defect dipoles, leading to a strong pinning effect after aging. The large asymmetrical strain is mainly attributed to two factors: The defect dipoles along crystallographic [001] direction destroy the long-range ordering of the ferroelectric and activate a reversible phase transition while promoting polarization rotation when the dipoles are aligned along the applied electric field. Our results not only demonstrate the potential application of BNT-based materials in low-frequency, large-stroke actuators but also provide a general methodology to achieve large strain.