Highly efficient spin-orbit torque and switching of layered ferromagnet Fe3GeTe2

TL;DR

This paper demonstrates highly efficient spin-orbit torque-induced switching in layered ferromagnet Fe3GeTe2, showing potential for advanced spintronic devices due to its large SOT efficiency and atomically flat interfaces.

Contribution

It reports the first measurement of large spin-orbit torque efficiency in monolayer vdW ferromagnet Fe3GeTe2, surpassing many 3D heterostructures.

Findings

SOT causes magnetization switching at 2.5x10^11 A/m^2 current density

SOT efficiency is comparable or larger than 3D ferromagnetic metal heterostructures

Atomically flat FGT/Pt interface enhances SOT efficiency

Abstract

Among van der Waals (vdW) layered ferromagnets, Fe3GeTe2 (FGT) is an excellent candidate material to form FGT/heavy metal heterostructures for studying the effect of spin-orbit torques (SOT). Its metallicity, strong perpendicular magnetic anisotropy built in the single atomic layers, relatively high Curie temperature (Tc about 225 K) and electrostatic gate tunability offer a tantalizing possibility of achieving the ultimate high SOT limit in monolayer all-vdW nanodevices. The spin current generated in Pt exerts a damping-like SOT on FGT magnetization. At about 2.5x1011 A/m2 current density,SOT causes the FGT magnetization to switch, which is detected by the anomalous Hall effect of FGT. To quantify the SOT effect, we measure the second harmonic Hall responses as the applied magnetic field rotates the FGT magnetization in the plane. Our analysis shows that the SOT efficiency is comparable with that of the best heterostructures containing three-dimensional (3D) ferromagnetic metals and much larger than that of heterostructures containing 3D ferrimagnetic insulators. Such large efficiency is attributed to the atomically flat FGT/Pt interface, which demonstrates the great potential of exploiting vdW heterostructures for highly efficient spintronic nanodevices.