Lead-free ferroelectrics with giant unipolar strain for high-precision actuators.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39103339.
- Also identified by DOI 10.1038/s41467-024-51082-6 and PMC identifier 11300602.
- Licence recorded as CC BY-NC-ND.
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Abstract
The trade-off between electrostrain and strain hysteresis for piezo/ferroelectric materials largely restrains the development of high precision actuators and remains unresolved over the past few decades. Here, a simple composition of (Bi<sub>0.5</sub>Na<sub>0.5</sub>)<sub>1-x/100</sub>Sr<sub>x/100</sub>TiO<sub>3</sub> in the ergodic relaxor state is collaboratively designed through the segregated domain structure with the ferroelectric core, local polarization heterogeneity, and defect engineering. The ferroelectric core can act as a seed to facilitate the field-induced nonpolar-to-polar transition. Together with the internal bias field caused by defect dipoles and adjusted through electric field cycling and heat treatment technology, a giant unipolar strain of 1.03% is achieved in the x = 30 ceramic with a low hysteresis of 27%, while the electric-field-independent large-signal piezoelectric strain coefficient of ~1000 pm/V and ultralow hysteresis of <10% can be obtained in the x = 35 ceramic. Intriguingly, the low-hysteresis high strain also exhibits near-zero remnant strain, excellent temperature and cycling stability.