Tailoring coercive fields and the Curie temperature via proximity coupling in WSe\(_2\)/Fe\(_3\)GeTe\(_2\) van der Waals heterostructures

Hybrid structures consisting of two-dimensional (2D) magnets and semiconductors have exhibited extensive functionalities in spintronics and opto-spintronics. In this work, we have fabricated WSe\(_2\)/Fe\(_3\)GeTe\(_2\) van der Waals (vdW) heterostructures and investigated the proximity effects on 2D magnetism. Through reflective magnetic circular dichroism (RMCD), we have observed a temperature-dependent modulation of magnetic order in the heterostructure. For temperatures above \(40\) K, WSe\(_2\)-covered Fe\(_3\)GeTe\(_2\) exhibits a larger coercive field than that observed in bare Fe\(_3\)GeTe\(_2\), accompanied by a noticeable enhancement of the Curie temperature by \(21\) K. This strengthening suggests an increase in magnetic anisotropy in the interfacial Fe\(_3\)GeTe\(_2\) layer, which can be attributed to the spin-orbit coupling (SOC) proximity effect induced by the adjacent WSe\(_2\) layers. However, at much lower temperatures (\(T