Magnon diffuse scattering in scanning transmission electron microscopy

TL;DR

This paper develops a theory and simulation showing that magnons can produce detectable atomic contrast in electron microscopy, with potential for spectral analysis using advanced detectors.

Contribution

It introduces a novel theoretical framework and simulation for magnon diffuse scattering in STEM, highlighting its detectability and spectral signatures.

Findings

Magnon diffuse scattering is significantly weaker than phonon scattering at 300 K.

Magnons can produce atomic contrast detectable by EELS with atomic-size electron beams.

Spectral signatures of magnons can be resolved with monochromated STEM and direct electron detectors.

Abstract

We present a theory and a simulation of thermal diffuse scattering due to the excitation of magnons in scanning transmission electron microscopy. The calculations indicate that magnons can present atomic contrast when detected by electron energy-loss spectroscopy using atomic-size electron beams. The results presented here indicate that the intensity of the magnon diffuse scattering in bcc iron at 300~K is 4 orders of magnitude weaker than the intensity of thermal diffuse scattering arising from atomic vibrations. In an energy range where the phonon and magnon dispersions do not overlap, a monochromated scanning transmission electron microscope equipped with direct electron detectors for spectroscopy is expected to resolve the magnon spectral signatures.