Giant Magnetic Anisotropy in the Atomically Thin van der Waals Antiferromagnet FePS₃

Abstract

Abstract Van der Waals (vdW) magnets are an ideal platform for tailoring 2D magnetism with immense potential for spintronics applications and are intensively investigated. However, little is known about the microscopic origin of magnetic order in these antiferromagnetic systems. X‐ray photoemission electron microscopy is used to address the electronic and magnetic properties of the vdW antiferromagnet FePS 3 down to the monolayer. The experiments reveal a giant out‐of‐plane magnetic anisotropy of 22 meV per Fe ion, accompanied by unquenched magnetic orbital moments. Moreover, the calculations suggest that the Ising magnetism in FePS 3 is a visible manifestation of spin–orbit entanglement of the Fe 3 d electron system.