In situ X-ray diffraction investigation of electric-field-induced switching in a hybrid improper ferroelectric.
In situ X-ray diffraction investigation of electric-field-induced switching in a hybrid improper ferroelectric.
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DOI：
10.1107/s1600576721001096
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发表时间：
2021-04-01
影响因子：
6.1
通讯作者：
Senn MS
中科院分区：
文献类型：
--
作者：
Clarke G;Ablitt C;Daniels J;Checchia S;Senn MS
本文报道了在外加电场作用下收集的第一个杂化反常铁电体原位衍射结果，该结果显示了通过八面体旋转模式展开进行的开关机制的微妙而强大的偏好。不适当的铁电机制正受到越来越多的研究，因为它们有可能扩大现有功能材料的目录，同时促进铁电性与其他技术上理想的性质（如铁磁性）之间的耦合。本文介绍了对Ca2.15Sr0.85Ti2O7样品进行的原位同步x射线衍射实验结果，以阐明该化合物中杂化铁电异常开关的机制。通过同时施加电场和记录衍射模式，上层结构峰强度的变化与由Nowadnick和Fennie [Phys]提出的一种开关机制一致。Rev. B,(2016), 94, 104105]。虽然实验只获得了部分响应，但与模拟数据的比较表明，在开关的初始阶段，涉及八面体旋转模式解绕的一步开关机制更受青睐。这些结果代表了一些首次报道的基于衍射的实验证据，证明了在不适当的铁电中开关机制。
This article reports the first in situ diffraction result collected under applied electric field on a hybrid improper ferroelectric which shows a subtle yet robust preference for a switching mechanism that proceeds via an unwinding of the octahedral rotation mode. 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 in situ synchrotron X-ray diffraction experiment performed on samples of Ca2.15Sr0.85Ti2O7 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 [Phys. Rev. B, (2016), 94, 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.