Prospect for measuring two-dimensional van der Waals magnets by electron magnetic chiral dichroism.

• The feasibility analysis of EMCD measurements in three orthogonal directions are conducted for 2D magnets to provide a guide for future experiments under zone axial orientation. • The low voltage EMCD technique is beneficial to 2D magnets at a ultrathin thickness. • The number of atomic layers could lead to a strong modulation of EMCD signals under zone axial orientation. • The slight beam tilt can be utilized to enhance the EMCD signals under zone axial orientation. • The SNR and required electron dose are quantitatively evaluated for EMCD measurement on 2D magnets. Two-dimensional (2D) van der Waals magnets have drawn considerable attention in recent years triggered by the huge interest in novel magnetism and spintronic devices. Magnetic measurement of 2D van der Waals (vdW) magnets is crucial to understand the physical origin of magnetism in 2D limits. Therefore, advanced magnetic characterization techniques are highly required. However, only a limited number of such techniques are available due to the extremely small volume of 2D vdW magnets. Here, we introduce the electron magnetic chiral dichroism (EMCD) technique in transmission electron microscope (TEM) to measure 2D vdW crystals. In comparison with some other already-employed techniques in 2D magnets, EMCD is able to quantitatively measure magnetic parameters in three orthogonal directions at nanometer or even at atomic scale. We then perform EMCD simulations on several typical 2D vdW magnets with respect to the accelerating voltage, the number of atomic layers and beam tilt under zone axial orientation. The intensity and distribution of EMCD signals in three orthogonal directions are given in the diffraction plane, thereby providing an optimized design to achieve EMCD measurements. Finally, we discuss the signal-to-noise-ratio and required electron dose in order to obtain a measurable EMCD signal for 2D vdW magnets. Our results provide a feasibility analysis and guideline to measure 2D vdW magnets in future experiments. [ABSTRACT FROM AUTHOR]