For decades, researchers have pursued lead-free alternatives to replace toxic yet high-performance lead-based antiferroelectrics (AFEs). Sodium niobate (NaNbO3, NN) emerged as a prime candidate due to its low cost and environmentally benign nature. However, its irreversible phase transition at room temperature, resulting in energy-wasting ferroelectric-like hysteresis, has hindered practical applications.
The team published their work in Journal of Advanced Ceramics on June 18, 2025.
Now, a materials scientists team has cracked this challenge through ions co-doping strategic. As published in Journal of Advanced Ceramics, co-doping NN with variable-valence elements Sn and Ce enables precise control of crystal structure and phase stability."Sn²⁺ and Ce³⁺ preferentially occupy A-sites, while Sn⁴⁺ and Ce⁴⁺ substitute B-site Nb⁵⁺," explained Prof. Cheng. "This dual-site doping shrinks the tolerance factor, stabilizing the antiferroelectric P-phase. More importantly, it enables the reversible field-induced phase transition absent in pure NN. Crucially, sintering atmosphere manipulation (N₂ vs. O₂) allowed selective tuning of Sn²⁺/Sn⁴⁺ and Ce³⁺/Ce⁴⁺ ratios, directing ions to specific lattice sites."
The x =0.04 composition exhibited a reversible antiferroelectric-to-ferroelectric transition, evidenced by a pristine double hysteresis loop. Accompanying this, an ultrahigh electro-strain of 0.38% was achieved at 60 kV/cm and with low strain hysteresis. The x =0.06 dominant ferroelectric Q-phase with minor AFE P-phas. Exceptionally stable dielectric constant (εᵣ ≈1250 from 1kHz–1MHz) with ultra-low loss (tanδ <0.025). "The x=0.06 composition's frequency-insensitive permittivity is ideal for power-storage capacitors,"noted first-author Dr. Fen Ye. "Meanwhile, the x=0.04 variant's near-zero strain hysteresis makes it perfect for precision actuators in micro-robotics or biomedical devices."
The team plans to:
Optimize microstructure to enhance breakdown strength in x=0.06;
Explore thin-film configurations for integrated devices;
Extend the doping strategy to other AFE systems.
About Author
Fen Ye: Assoc. Prof. @ Jingdezhen University. Hao Cheng: Prof. @ Jingdezhen University. Xiangping Jiang: Prof. @ Jingdezhen Ceramic University. Lifeng Zhu: Assoc. Prof. @ University of Science and Technology Beijing. Wei Shi: Prof. @ Tongren University. Jiahao Xue:Master's degree student @ Tongren University.
About Journal of Advanced Ceramics
Journal of Advanced Ceramics (JAC) is an international academic journal that presents the state-of-the-art results of theoretical and experimental studies on the processing, structure, and properties of advanced ceramics and ceramic-based composites. JAC is Fully Open Access, monthly published by Tsinghua University Press, and exclusively available via SciOpen . JAC's 2024 IF is 16.6, ranking in Top 1 (1/33, Q1) among all journals in "Materials Science, Ceramics" category, and its 2024 CiteScore is 25.9 (5/130) in Scopus database. ResearchGate homepage: https://www.researchgate.net/journal/Journal-of-Advanced-Ceramics-2227-8508
