Proximity coupling of graphene to a 2D silicene magnet

Abstract

2D magnets attract significant attention due to the variety and tunability of their properties, prospects in ultra-compact spintronics. Their range of applications can be expanded significantly by coupling with nonmagnetic 2D layers to produce functional heterostructures. In these endeavors, graphene plays the central role – the emerging magnetic proximity effects drive applications in spin-based devices. However, development of graphene heterostructures with 2D f-magnets, notable for unconventional magnetic structures and properties, lags behind. Here, we report synthesis of the trilayer heterostructure GdSi₂/Gr/GdSi₂ with magnetism stemming from half-filled 4f-shells of Gd ions. Remarkably, the graphene interlayer results in doubling the magnetic transition temperature of the silicene-based 2D magnet GdSi₂. Caused by proximity to the 2D magnet, the electron transport in graphene demonstrates negative magnetoresistance and the anomalous Hall effect, pointing at spin polarization of carriers. Magnetic signals and proximity effects in GdSi₂/Gr/GdSi₂ are much stronger than those in graphene heterostructures with rare-earth metal superlattices whereas the effective mass of carriers is kept rather low suggesting that the advantageous properties of graphene are preserved. The GdSi₂/Gr/GdSi₂ system is integrated with the ubiquitous Si semiconductor platform. The developed synthetic approach provides a route to a class of magnetic heterostructures coupled with technological semiconductors.