Development of precession Lorentz transmission electron microscopy

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 (θ), we show that diffraction contrast is significantly reduced with increasing θ. However, large θ values lead to an undesired broadening of the magnetic contrast, highlighting the importance of optimizing θ. Furthermore, defocus-dependent measurements reveal that magnetic contrast is particularly improved at small defocus values. These findings demonstrate the potential of precession LTEM as a powerful technique for studying magnetic dynamics.