Scientists can now detect magnetic behavior at the atomic level with a new electron microscopy technique developed by a team from the Department of Energy's Oak Ridge National Laboratory and Uppsala University, Sweden. The researchers took a counterintuitive approach by taking advantage of optical distortions that they typically try to eliminate.

 

"It's a new approach to measure magnetism at the atomic scale," ORNL's Juan Carlos Idrobo said. "We will be able to study materials in a new way.



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Ref:  Detecting magnetic ordering with atomic size electron probes.  *Advanced Structural and Chemical Imaging* (27 May 2016) | DOI: 10.1186/s40679-016-0019-9 | PDF (Open Access)

 

ABSTRACT

Although magnetism originates at the atomic scale, the existing spectroscopic techniques sensitive to magnetic signals only produce spectra with spatial resolution on a larger scale. However, recently, it has been theoretically argued that atomic size electron probes with customized phase distributions can detect magnetic circular dichroism. Here, we report a direct experimental real-space detection of magnetic circular dichroism in aberration-corrected scanning transmission electron microscopy (STEM). Using an atomic size-aberrated electron probe with a customized phase distribution, we reveal the checkerboard antiferromagnetic ordering of Mn moments in LaMnAsO by observing a dichroic signal in the Mn L-edge. The novel experimental setup presented here, which can easily be implemented in aberration-corrected STEM, opens new paths for probing dichroic signals in materials with unprecedented spatial resolution.