Spintronic properties of Fe-based van der Waals materials

Abstract

Magnetism in two dimensions has been a key area of research in the field of magnetic materials and devices. The discovery of graphene, a two-dimensional (2D) van der Waals (vdW) material, has led to a particular focus on the potential for intrinsic 2D magnetism in vdW material. Since the first successful creation of a ferromagnetic monolayer using a vdW material, CrI3, in 2017, researchers have been exploring the use of various vdW magnets to produce atomically thin layers with high crystallinity, which can be assembled with other vdW materials to create atomically flat and sharp interfaces. Early research on vdW magnets has primarily focused on insulating materials such as CrX3 (X = halogens), CrMTe3 (M = Si, Ge), and TmPCh3 (Tm = transition metals, Ch = chalcogens), while metallic vdW ferromagnets such as Cr1/3TaS2, Fe1/4TaS2, FenGeTe2 (n = 3,4,5), and 1T-CrTe2, which show room temperature ferromagnetic order, are also being widely studied. The isolation of monolayers and the creation of their heterostructures have led to the discovery of a range of exceptional transport, optical, and spin-related properties, which hold promise for the development of spintronic functionalities. Graphene, a particularly effective spin-channel material that exhibits a spin relaxation length of several micrometers even at room temperature, has been successfully used to realize spin current injection and detection through techniques such as the use of magnetic tunneling junctions with 2D vdW ferromagnets and optical spin injection using TMDC/graphene heterostructures. Researchers are also exploring various techniques, such as spin-orbit torque and voltage-induced magnetization control, to manipulate spin information and create fast and energy-efficient spintronic devices.