One Site, Two Cations, Three Environments: s2 and s0 Electronic Configurations Generate Pb-Free Relaxor Behavior in a Perovskite Oxide



Surta, T Wesley ORCID: 0000-0002-2882-6483, Whittle, Thomas A, Wright, Matthew A, Niu, Hongjun, Gamon, Jacinthe, Gibson, Quinn D, Daniels, Luke M ORCID: 0000-0002-7077-6125, Thomas, William J, Zanella, Marco ORCID: 0000-0002-6164-6169, Shepley, Philippa M
et al (show 6 more authors) (2021) One Site, Two Cations, Three Environments: s2 and s0 Electronic Configurations Generate Pb-Free Relaxor Behavior in a Perovskite Oxide. Journal of the American Chemical Society.

[img] Text
KBMN-KBT_resubmission_Final.pdf - Accepted Version

Download (12MB) | Preview

Abstract

The piezoelectric devices widespread in society use noncentrosymmetric Pb-based oxides because of their outstanding functional properties. The highest figures of merit reported are for perovskites based on the parent Pb(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub> (PMN), which is a relaxor: a centrosymmetric material with local symmetry breaking that enables functional properties, which resemble those of a noncentrosymmetric material. We present the Pb-free relaxor (K<sub>1/2</sub>Bi<sub>1/2</sub>)(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub> (KBMN), where the thermal and (di)electric behavior emerges from the discrete structural roles of the s<sup>0</sup> K<sup>+</sup> and s<sup>2</sup> Bi<sup>3+</sup> cations occupying the same A site in the perovskite structure, as revealed by diffraction methods. This opens a distinctive route to Pb-free piezoelectrics based on relaxor parents, which we demonstrate in a solid solution of KBMN with the Pb-free ferroelectric (K<sub>1/2</sub>Bi<sub>1/2</sub>)TiO<sub>3</sub>, where the structure and function evolve together, revealing a morphotropic phase boundary, as seen in PMN-derived systems. The detailed multiple-length-scale understanding of the functional behavior of KBMN suggests that precise chemical manipulation of the more diverse local displacements in the Pb-free relaxor will enhance performance.

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 26 Jan 2021 08:18
Last Modified: 15 Oct 2021 17:27
DOI: 10.1021/jacs.0c10572
Open Access URL: https://doi.org/10.1021/jacs.0c10572
URI: https://livrepository.liverpool.ac.uk/id/eprint/3114818