Tailoring coercive fields and the Curie temperature via proximity coupling in WSe${}_2$/Fe${}_3$GeTe${}_2$ van der Waals heterostructures

Abstract

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 ($T<20$ K), a non-monotonic modification of the coercive field is observed, showing both reduction and enhancement, which depends on the thickness of the WSe${}_2$ and Fe${}_3$GeTe${}_2$ layers. Moreover, an unconventional two-step magnetization process emerges in the heterostructure, indicating the short-range nature of SOC proximity effects. Our findings revealing proximity effects on 2D magnetism may shed light on the design of future spintronic and memory devices based on 2D magnetic heterostructures.

References in corpus (13)

• Spintronics: Fundamentals and applications
• 2D materials and van der Waals heterostructures
• Layer-dependent Ferromagnetism in a van der Waals Crystal down to the Monolayer Limit
• Gate-tunable Room-temperature Ferromagnetism in Two-dimensional Fe${}_3$GeTe${}_2$
• Evolution of Electronic Structure in Atomically Thin Sheets of WS2 and WSe2
• Two-Dimensional Itinerant Ising Ferromagnetism in Atomically thin Fe3GeTe2
• Van der Waals heterostructures for spintronics and opto-spintronics
• Layer-Resolved Magnetic Proximity Effect in van der Waals Heterostructures
• Recent progress and challenges in magnetic tunnel junctions with 2D materials for spintronic applications
• Proximity exchange effects in MoSe${}_2$ and WSe${}_2$ heterostructures with CrI${}_3$: twist angle, layer, and gate dependence
• Interplay between spin proximity effect and charge-dependent exciton dynamics in MoSe${}_2$ / CrBr${}_3$ van der Waals heterostructures
• Great enhancement of Curie temperature and magnetic anisotropy in two-dimensional van der Waals magnetic semiconductor heterostructures
• Interface-enhanced ferromagnetism with long-distance effect in van der Waals semiconductor