Beyond phase boundaries: atomic mechanisms governing structure and property variations in (K, Na)NbO<sub>3</sub>-based ferroelectrics.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41390339.
- Also identified by DOI 10.1038/s41467-025-67573-z and PMC identifier 12827472.
- Licence recorded as CC BY-NC-ND.
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Abstract
Chemical dopants-induced phase boundary engineering has boosted electrical properties of (K, Na)NbO<sub>3</sub>-based piezoceramics, yet the underlying mechanisms governing these improvements remain unclear. Here, we elucidate these mechanisms through comprehensive multi-scale structural analysis (atomic-to-nanoscale-to-mesoscale) on two representative solid-solutions, namely (K, Na, Li)NbO<sub>3</sub> and (K, Na)NbO<sub>3</sub>-(Bi<sub>0.5</sub>Na<sub>0.5</sub>)ZrO<sub>3</sub>. By utilizing neutron pair distribution function analysis, scanning transmission electron microscope, first-principle calculations, and phase-field simulations, our results reveal distinct atomic-scale mechanism underlying phase boundary engineering. In (K, Na, Li)NbO<sub>3</sub>, convergent off-center displacements of Li atoms induce an interplay between displacive and order-disorder phase transition; while in (K, Na)NbO<sub>3</sub>-(Bi<sub>0.5</sub>Na<sub>0.5</sub>)ZrO<sub>3</sub>, divergent off-center displacements of Bi atoms trigger a predominant order-disorder type phase transition. These atomic-scale structural characteristics directly correlate with mesoscopic ferroelectric domains and ultimately determine macroscopic electrical properties. This work elucidates the role of chemical dopants in phase boundary engineering from a multi-scale perspective, establishing a framework for designing lead-free piezoceramics with enhanced electrical properties and advancing the development of eco-friendly piezoceramics.