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

Surta, TW, Whittle, Thomas, Wright, Matthew, Niu, Hongjun, Gamon, Jacinthe, Gibson, Quinn, Daniels, Luke, Zanella, Marco, Shepley, PM, Li, Y, Goetzee-Barral, A, Bell, AJ, Alaria, Jonathan, Claridge, John and Rosseinsky, Matthew (2020) One Site, Two Cations, Three Environments: s2 and s0 Electronic Configurations Generate Pb-Free Relaxor Behavior in a Perovskite Oxide. [Data Collection]

Data Catalogue DOI: 10.17638/datacat.liverpool.ac.uk/1041

Description

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(Mg1/3Nb2/3)O3 (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 (K1/2Bi1/2)(Mg1/3Nb2/3)O3 (KBMN), where the thermal and (di)electric behavior emerges from the discrete structural roles of the s0 K+ and s2 Bi3+ 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 (K1/2Bi1/2)TiO3, 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.

Keywords:

Piezoelectrics, relaxors, Pb-free

Divisions:

Faculty of Science and Engineering > School of Physical Sciences

Depositing User:

Wesley Surta

Date Deposited:

23 Mar 2021 10:41

Last Modified:

23 Mar 2021 10:41

DOI:

10.17638/datacat.liverpool.ac.uk/1041