Multi-Angle Beam Scanning Transmission Electron Microscopy for Diffraction-Contrast-Free Magnetic Imaging

Abstract

Recent development of the differential phase contrast (DPC) scanning transmission electron microscopy (STEM) technique has significantly advanced materials science supported by high-sensitivity detectors and powerful data processing. Especially the 4D-STEM technique, employing a pixelated camera as a STEM detector, enables extensive information acquisition through post-processing of large datasets. However, magnetic or electric field imaging using DPC is often disturbed by diffraction contrasts intrinsic to the crystalline material. In this paper, we demonstrate elimination of the diffraction contrasts for magnetic field imaging by using angularly distributed multiple electron beams generated by a multi-hole aperture within the 4D-STEM framework. This multi-angle beam configuration suppresses irrelevant crystalline contrast and yields direct magnetic information with high sensitivity from the specimen. Furthermore, we performed various image analysis to extract and interpret magnetic domain structures and domain walls.