Electron energy-loss magnetic chiral dichroism (EMCD) in a transmission electron microscope allows the quantification of the magnetic structure of crystalline materials down to the nanometer scale [1-3]. However, restricted by a confined diffraction geometry applied in EMCD experiments , no experiments or theories have yet been performed to obtain EMCD signals for amorphous materials, due to their lack of long range ordering.
In this work, we for the first time demonstrate it is possible to detect element-specific magnetic signals in amorphous materials utilizing a single-crystalline overlayer as an EMCD beam splitter. The approach is applied to a bilayer sample where a very thin amorphous magnetic FeOx layer is grown on a single-crystalline Yttrium-stabilized ZrO2 substrate. We found that both experimental results and theoretical calculations lead to unprecedented EMCD signals. The quantitative orbital to spin magnetic moment ratio of Fe in amorphous FeOx layer has been acheived.
Our approach allows us to break through the constraint of crystal formats in EMCD spectra measurements, providing new prospects of detecting EMCD signals from amorphous and ultrathin materials at the nanometer scale. This approach might also be extended to the magnetic quantitative analysis of other heterogeneous materials at high spatial resolution.
This work may open a door to meet the challenge of exploring magnetic states and behaviors of amorphous films, and have important consequences for revealing the magnetic structures of magnetic materials in various crystal forms at the nanoscale using transmission electron microscopy.
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This work was financially supported by National 973 Project of China (2015CB921700, 2015CB654902), National Natural Science Foundation of China (51471096, 11374174, 51390471 and 51322101), Tsinghua University Initiative Scientific Research Program and National High Technology Research and Development Program of China (2014AA032904). This work made use of the resources of the National Center for Electron Microscopy in Beijing and Tsinghua National Laboratory for Information Science and Technology. J.R. acknowledges financial support of Swedish Research Council, STINT and Göran Gustafsson’s Foundation. H.L. Xin. acknowledges support from the Center for Functional Nanomaterials, which is a U.S. DOE Office of Science Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704. We are grateful to Prof. R. Yu, Dr. Y. Shao, Mrs. Z.Y. Cheng, Mr. D.S. Song for beneficial discussions, and Prof. P. Yu, Dr. Z.P. Li and Mr. Z.Y. Liao for providing the substrate and preparing the specimen.
To cite this abstract:Xiaoyan Zhong, Jie Lin, Song Cheng, Jan Rusz, Huolin Xin, Bing Cui, Kocevski Vancho, Lili Han, Jing Zhu; Detection of magnetic circular dichroism in amorphous materials utilizing a single-crystalline overlayer. The 16th European Microscopy Congress, Lyon, France. https://emc-proceedings.com/abstract/detection-of-magnetic-circular-dichroism-in-amorphous-materials-utilizing-a-single-crystalline-overlayer/. Accessed: December 14, 2019
EMC Abstracts - https://emc-proceedings.com/abstract/detection-of-magnetic-circular-dichroism-in-amorphous-materials-utilizing-a-single-crystalline-overlayer/