1. Lead-free ferroelectrics with giant unipolar strain for high-precision actuators.
- Author
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Zhou, Xuefan, Zhang, Jun, Luo, Hang, Zhang, Yan, Tang, Shiyu, Huang, Houbing, Yuan, Xi, Song, Miao, Qi, He, and Zhang, Dou
- Subjects
FERROELECTRIC materials ,HYSTERESIS ,ELECTRIC fields ,FERROELECTRIC crystals ,THERMODYNAMIC cycles ,RELAXOR ferroelectrics - 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
0.5 Na0.5 )1-x/100 Srx/100 TiO3 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. The development of precision piezo/ferroelectric actuators is hindered by the trade-off between electrostrain and strain hysteresis. Here, the authors report ferroelectric cores embedded into ergodic relaxor phase shells, showing giant unipolar strain and low hysteresis. [ABSTRACT FROM AUTHOR]- Published
- 2024
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