Proximity‐Coupling‐Induced Significant Enhancement of Coercive Field and Curie Temperature in 2D van der Waals Heterostructures

Magnetism in 2D has long been the focus of condensed matter physics due to its important applications in spintronic devices. A particularly promising aspect of 2D magnetism is the ability to fabricate 2D heterostructures with engineered optical, electrical, and quantum properties. Recently, the discovery of intrinsic ferromagnetisms in atomic thick materials has provided a new platform for investigations of fundamental magnetic physics. In contrast to 2D CrI3 and Cr2Ge2Te6 insulators, itinerant ferromagnetic Fe3GeTe2 (FGT), which has a larger intrinsic perpendicular anisotropy, higher Curie temperature (TC), and relatively better stability, is a promising candidate for achieving permanent room‐temperature ferromagnetism through interface or component engineering. Here, it is shown that the ferromagnetic properties of FGT thin flakes can be modulated through coupling with a FePS3. The magneto‐optical Kerr effect results show that the TC of FGT is improved by more than 30 K and that the coercive field is increased by ≈100% due to the proximity coupling effect, which changes the spin textures of FGT at the interface. This work reveals that antiferromagnet/ferromagnet coupling is a promising way to engineer the magnetic properties of itinerant 2D ferromagnets, which paves the way for applications in advanced magnetic spintronic and memory devices. Significant enhancements of Curie temperature (TC) and coercive field (HC) are achieved in ultrathin Fe3GeTe2 (FGT) flakes by using the proximity effect between FGT and FePS3 (FPS). The TC is improved by more than 30 K and the HC is increased by ≈100%, which makes 2D FPS/FGT heterostructures promising candidates for applications in magnetic sensors and storage devices.