Magnetization Reversal Behavior in van der Waals Ferromagnet, Fe₃GeTe₂

The realization of novel non-trivial topological spin textures such as skyrmions and merons in magnetic van der Waals (vdW) materials is opening new opportunities for harnessing them for spintronics as well as energy-efficient computing. An advantage of vdW ferromagnets is the ability to create novel heterostructures without strict requirements of epitaxy as well as using interfacial interactions such as proximity effects to create novel functionality. A fundamental understanding of the magnetization reversal process and how it is affected by the thickness of the vdW materials is necessary so as to control their magnetic behavior. In this work, we will present the magnetic reversal behavior of Fe₃GeTe₂ with varying thickness. We have performed an in-situ study and directly imaged the magnetic domain structure under varied temperature and external magnetic fields using cryo-Lorentz transmission electron microscopy (LTEM). We will discuss the reversal behavior and the effect of thickness as well as edges and thickness steps on formation of novel pattern of domains. Through combination of micromagnetic simulations and the experimental data, we gain an understanding of the underlying energy landscape that governs this behavior.