Direct observation of modulation structure in room-temperature multiferroic Bi4.2K0.8Fe2O9+δ. (15th April 2021)

• Record Type: Journal Article
• Authors: Zhang, Lu; Tian, Huanfang; Dong, Sining; Yang, Dong; Li, Xiaoguang; Li, Jun; Li, Jianqi; Yang, Huaixin
• Is Part Of: Scripta materialia. Number 196(2021)
• Publication Date: 2021-04-15
• Subjects: Structural modulation -- Scanning transmission electron microscopy -- Nanobelts; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2021.113752
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: The coexistence and coupling between alternatively stacked layers with different functional properties often give rise to exotic physical phenomena, such as high-temperature superconductivity, multiferroic behavior, and giant thermoelectric performance, which are tightly linked with the intrinsic microstructures. Here we unambiguously uncover the structural modulations in multiferroic Bi4.2 K0.8 Fe2 O9+δ (BKFO) nanobelts with a magnetoelectric–dielectric superlattice by scanning transmission electron microscopy (STEM). The octahedrons in the perovskite layers are identified as FeO6 and the ordered arrangements of the Bi and K cations are clearly determined. Quantitative measurements of the positions of the Bi columns indicate that the displacive modulations can be decomposed into a transverse wave and a longitudinal wave, whose amplitudes and phases are layer-dependent. This study may help to understand and optimize the magnetoelectric coupling effect in BKFO. Graphical abstract: Image, graphical abstract