Electric Field-Induced Magnetic Anisotropies in Fe₃GeTe₂-Based Nanoheterostructures

Van der Waals two-dimensional (2D) ferromagnets provide a new way for constructing low-power and high-quality spintronic devices owing to their long-range ferromagnetic ordering in ultrathin thickness. Here, we investigated the magnetic anisotropy of bulk Fe 3 GeTe 2 (FGT) and magneto-transport properties of the FGT nanosheet by experiment and studied the electric field-induced magnetic anisotropy energy (MAE) of monolayer FGT and the FGT/graphene heterojunction by density functional theory. Both results show that the easy magnetization direction of FGT is perpendicular to the plane of the material. The MAE of the monolayer FGT is 1124 μeV/Fe in an electric field of 0 V/Å, which is much higher than that of 53 μeV/Fe in an electric field of 0.6 V/Å. For the FGT/graphene heterojunction, the MAE can be tailored from 1239 μeV/Fe at 0 V/Å to 1167 μeV/Fe at 0.5 V/Å. In origin, the magnetic anisotropy of monolayer FGT and the FGT/graphene heterojunction can be effectively modulated by the electric field owing to the d-orbital filling and interlayer charge redistribution, respectively. This work explains the internal mechanism of the magnetic anisotropy regulation of monolayer FGT and the FGT/graphene heterojunction under an electric field and provides a crucial step toward the design and development of next-generation spintronic devices based on 2D ferromagnetic heterojunctions.