Correlating hidden local structural distortion with antiferroelectric-ferroelectric transition in PbZrO 3-based perovskites

Externally stimulated antiferroelectric-ferroelectric (AFE-FE) transition makes AFE materials attractive for many applications ranging from energy storage to sensing. This transition-mediated macroscopic elec-trical characteristics have been extensively investigated, yet the underlying structural evolution remains poorly understood. Herein, we study the local-and long-range structural evolutions in the Nb-doped Pb(Zr,Sn,Ti)O3 perovskites by in-situ X-ray total scattering and diffraction, which show three different types of AFE-FE transitions. The evolution of long-range structure from diffraction and local structure identified by atomic pair distribution function (PDF) are consistent well with the phase transition behav-ior indicated by macroscopic polarization/strain measurements, while discrepancies exist. Interestingly, frequently employed long-range structure picture that the uniform AFE pseudo-tetragonal to FE rhom-bohedral transformation is insufficient to understand the distinct composition-dependent AFE-FE transi-tion behaviours. Instead, the reversibility of this transition correlates with the chemically sensitive local atomic displacements revealed by newly developed in-situ PDF. The critical electric field of transition is associated with the local structural differences between the AFE and FE state. The macroscopic electros-trains can be well estimated by the phase transition associated lattice strain and domain alignment from in-situ synchrotron XRD data, while the local strains calculated from in-situ PDFs are found to be much lower. These results provide a fresh insight into the AFE-FE transition, and advance the understanding of structure-property relationships in AFE materials.(c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.