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.

Two-dimensional (2D) ferromagnetism has attracted intense attention as it provides a platform for investigations of fundamental physics and the emerged devices. Recently, the discovery of intrinsic 2D ferromagnets enables people...

Fe3GeTe2/MnPS3 and Fe3GeTe2/MnPSe3 van der Waals heterostructures were fabricated by mechanical exfoliation. Via the magneto-optical Kerr effect and reflected magnetic circular dichroism measurements, we have observed nearly three times enhancement of the coercive field, improvement of Curie temperature, and exchange bias effect in both heterostructures. These observations may provide new insights into the emergent heterostructure devices between itinerant ferromagnets and metal thio- and selenophosphates for both applied and fundamental research studies in magnetic correlations.

Silver-coated gold nanorods (GNRs) with large longitudinal surface plasmon resonance (SPR) wavelength tunability were fabricated by depositing silver (Ag) on the surface of GNRs. Linear and third-order optical nonlinear properties together with the ultrafast response time of these nanorods were investigated. The results demonstrate that the longitudinal SPR wavelength of GNRs is very sensitive to the thickness (t Ag ) of the Ag coating layer, which changes the dielectric constant of the environment. As t Ag increases from 0 to 15 nm, the SPR wavelength decreases dramatically from 840 to 520 nm, the corresponding wavelength-dependent third-order optical susceptibility changes dependently with the changing of the SPR absorption curve while the one-photon and two-photon figures of merit were required for optical switching applications, and the ultrafast response time also changes continuously with varying SPR wavelength. These observations are important for applications of plasmonic structures in ultrafast wavelength division multiplexing devices.