Continuous manipulation of magnetic anisotropy in a van der Waals ferromagnet via electrical gating

Controlling the magnetic anisotropy of ferromagnetic materials is key to the development of magnetic switching devices and spintronic applications. The intrinsic magnetic anisotropy of such materials is typically fixed along a particular direction—the magnetic easy axis. However, if the magnetic anisotropy could be continuously modulated, this could be used to create multifunctional devices. Here we report the gate-tunable modulation of magnetic anisotropy—from an initial out-of-plane to a canted orientation and then finally to an in-plane orientation—in the van der Waals ferromagnet Fe₅GeTe₂. We use angle-dependent anomalous Hall effect measurements and magneto-optical Kerr effect measurements, combined with quantitative Stoner–Wohlfarth analysis, to show that the magnetic easy axis continuously rotates via a spin-flop pathway and can be modulated in a large range from 2.11 to −0.38 MJ m^–3. The tuning of anisotropy can also be achieved by modulating the temperature.