Clarke Gabriel, Ablitt Chris, Daniels John, Checchia Stefano, Senn Mark S
Department of Chemistry, University of Warwick, Coventry, United Kingdom.
School of Materials Science and Engineering, UNSW Sydney, Kensington 2052, Australia.
J Appl Crystallogr. 2021 Mar 18;54(Pt 2):533-540. doi: 10.1107/S1600576721001096. eCollection 2021 Apr 1.
Improper ferroelectric mechanisms are increasingly under investigation for their potential to expand the current catalogue of functional materials whilst promoting couplings between ferroelectricity and other technologically desirable properties such as ferromagnetism. This work presents the results of an synchrotron X-ray diffraction experiment performed on samples of CaSrTiO in an effort to elucidate the mechanism of hybrid improper ferroelectric switching in this compound. By simultaneously applying an electric field and recording diffraction patterns, shifts in the intensity of superstructure peaks consistent with one of the switching mechanisms proposed by Nowadnick & Fennie [, (2016), , 104105] are observed. While the experiment only achieves a partial response, comparison with simulated data demonstrates a preference for a one-step switching mechanism involving an unwinding of the octahedral rotation mode in the initial stages of switching. These results represent some of the first reported experimental diffraction-based evidence for a switching mechanism in an improper ferroelectric.
人们越来越关注不当铁电机制，因为它们有潜力扩展当前功能材料的种类，同时促进铁电性与其他技术上理想的特性（如铁磁性）之间的耦合。这项工作展示了对CaSrTiO样品进行同步加速器X射线衍射实验的结果，旨在阐明该化合物中混合不当铁电开关的机制。通过同时施加电场并记录衍射图案，观察到超结构峰强度的变化与Nowadnick和Fennie [, (2016),, 104105]提出的一种开关机制一致。虽然实验仅实现了部分响应，但与模拟数据的比较表明，在开关的初始阶段，更倾向于一种涉及八面体旋转模式展开的一步开关机制。这些结果代表了首次报道的基于实验衍射的不当铁电体开关机制的一些证据。
