Microscopic origins of the large piezoelectricity of leadfree (Ba,Ca)(Zr,Ti)O<sub>3</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28631724.
- Also identified by DOI 10.1038/ncomms15944 and PMC identifier 5481827.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
In light of directives around the world to eliminate toxic materials in various technologies, finding lead-free materials with high piezoelectric responses constitutes an important current scientific goal. As such, the recent discovery of a large electromechanical conversion near room temperature in (1-x)Ba(Zr<sub>0.2</sub>Ti<sub>0.8</sub>)O<sub>3</sub>-x(Ba<sub>0.7</sub>Ca<sub>0.3</sub>)TiO<sub>3</sub> compounds has directed attention to understanding its origin. Here, we report the development of a large-scale atomistic scheme providing a microscopic insight into this technologically promising material. We find that its high piezoelectricity originates from the existence of large fluctuations of polarization in the orthorhombic state arising from the combination of a flat free-energy landscape, a fragmented local structure, and the narrow temperature window around room temperature at which this orthorhombic phase is the equilibrium state. In addition to deepening the current knowledge on piezoelectricity, these findings have the potential to guide the design of other lead-free materials with large electromechanical responses.