Development of precession Lorentz transmission electron microscopy

TL;DR

This paper introduces a precession LTEM system that reduces diffraction contrast and enhances magnetic imaging resolution, enabling better study of magnetic textures and their dynamics.

Contribution

The study develops a precession LTEM method that suppresses diffraction contrast and improves magnetic imaging resolution, advancing magnetic texture analysis.

Findings

Diffraction contrast decreases with increasing precession angle.

Large precession angles cause broadening of magnetic contrast.

Optimal defocus settings improve magnetic contrast at small angles.

Abstract

Lorentz transmission electron microscopy (LTEM) is a powerful tool for high-resolution imaging of magnetic textures, including their dynamics under external stimuli and ultrafast nonequilibrium conditions. However, magnetic imaging is often hindered by non-magnetic diffraction contrast arising from inhomogeneous sample deformation or a non-parallel electron beam. In this study, we develop a precession LTEM system that can suppress diffraction contrast by changing the incident angle of the electron beam relative to the sample in a precessional manner. By comparing LTEM images acquired at different precession angles ($\theta$), we show that diffraction contrast is significantly reduced with increasing $\theta$. However, large $\theta$ values lead to an undesired broadening of the magnetic contrast, highlighting the importance of optimizing $\theta$. Furthermore, defocus-dependent measurements reveal that magnetic contrast is particularly improved at small defocus values, suggesting that precession LTEM can achieve higher spatial resolution. These findings demonstrate the potential of precession LTEM as a powerful technique for studying magnetic dynamics.