JEOL Ltd., Tokyo, Japan.
Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Tokyo, Japan.
Nature. 2022 Feb;602(7896):234-239. doi: 10.1038/s41586-021-04254-z. Epub 2022 Feb 9.
Characterizing magnetic structures down to atomic dimensions is central to the design and control of nanoscale magnetism in materials and devices. However, real-space visualization of magnetic fields at such dimensions has been extremely challenging. In recent years, atomic-resolution differential phase contrast scanning transmission electron microscopy (DPC STEM) has enabled direct imaging of electric field distribution even inside single atoms. Here we show real-space visualization of magnetic field distribution inside antiferromagnetic haematite (α-FeO) using atomic-resolution DPC STEM in a magnetic-field-free environment. After removing the phase-shift component due to atomic electric fields and improving the signal-to-noise ratio by unit-cell averaging, real-space visualization of the intrinsic magnetic fields in α-FeO is realized. These results open a new possibility for real-space characterization of many magnetic structures.
在材料和器件中，对纳米尺度磁体的设计和调控，关键在于对磁结构进行原子级分辨的描述。然而，在如此尺度下对磁场进行实空间成像极具挑战性。近年来，原子分辨微分相衬扫描透射电子显微镜（DPC STEM）的发展使得对单个原子内部的电场分布进行直接成像成为可能。本工作在无外加磁场的环境中，利用原子分辨 DPC STEM 对反铁磁赤铁矿（α-FeO）内部的磁场分布进行了实空间成像。通过去除原子电场引起的相移分量，并通过晶胞平均提高信噪比，实现了对α-FeO 本征磁场的实空间可视化。这些结果为许多磁结构的实空间表征开辟了新的可能性。
