[Paper Review] Room-temperature van der Waals 2D ferromagnet switching by spin-orbit torques

Weihao Li, Wenkai Zhu+11 more|arXiv (Cornell University)|Apr 21, 2023

2D Materials and ApplicationsMaterials Science3 citations

TL;DR

This study demonstrates electrically driven, room-temperature switching of perpendicular magnetization in a two-dimensional van der Waals ferromagnet, Fe3GaTe2, via spin-orbit torques (SOTs) in a Fe3GaTe2/Pt heterostructure. With a low current density of 1.3 × 10⁷ A/cm² and a high SOT efficiency of ξ_DL ≈ 0.22, the work achieves deterministic magnetization reversal at 300 K, enabling practical spintronic applications in atomically thin magnetic devices.

ABSTRACT

Emerging wide varieties of the two-dimensional (2D) van der Waals (vdW) magnets with atomically thin and smooth interfaces holds great promise for next-generation spintronic devices. However, due to the lower Curie temperature of the vdW 2D ferromagnets than room temperature, electrically manipulating its magnetization at room temperature has not been realized. In this work, we demonstrate the perpendicular magnetization of 2D vdW ferromagnet Fe3GaTe2 can be effectively switched at room temperature in Fe3GaTe2/Pt bilayer by spin-orbit torques (SOTs) with a relatively low current density of 1.3 10^7A/cm2. Moreover, the high SOT efficiency of ξ_{DL}~0.22 is quantitatively determined by harmonic measurements, which is higher than those in Pt-based heavy metal/conventional ferromagnet devices. Our findings of room-temperature vdW 2D ferromagnet switching by SOTs provide a significant basis for the development of vdW-ferromagnet-based spintronic applications.

Motivation & Objective

• To achieve electrically controlled magnetization switching in a 2D van der Waals ferromagnet at room temperature.
• To overcome the challenge of low Curie temperature in 2D vdW magnets that limits room-temperature operation.
• To demonstrate spin-orbit torque (SOT)-induced switching in a Fe3GaTe2/Pt heterostructure with high efficiency and low current density.
• To quantify the SOT efficiency in 2D vdW ferromagnetic heterostructures using harmonic measurements.

Proposed method

• Fabrication of a Fe3GaTe2/Pt bilayer heterostructure with atomically thin, clean interfaces.
• Application of in-plane current to generate spin-orbit torques (SOTs) via the Rashba effect in Pt.
• Use of harmonic voltage measurements to quantitatively determine the SOT efficiency (ξ_DL).
• Measurement of magnetization switching dynamics using the anomalous Hall effect under varying current pulses.
• Characterization of perpendicular magnetic anisotropy (PMA) in Fe3GaTe2 at room temperature.
• Validation of switching fidelity and current density dependence through repeated cycling and hysteresis loop analysis.

Experimental results

Research questions

• RQ1 Can spin-orbit torques induce deterministic magnetization switching in a 2D van der Waals ferromagnet at room temperature?
• RQ2 What is the minimum current density required to achieve SOT-induced switching in Fe3GaTe2/Pt heterostructures?
• RQ3 How does the SOT efficiency in 2D vdW ferromagnets compare to conventional heavy metal/ferromagnet systems?
• RQ4 What is the role of interfacial spin-orbit coupling in enabling efficient SOT switching in atomically thin 2D magnets?
• RQ5 Can the switching be achieved with high fidelity and reproducibility under ambient conditions?

Key findings

• Room-temperature switching of perpendicular magnetization in Fe3GaTe2 was successfully demonstrated using spin-orbit torques.
• A low current density of 1.3 × 10⁷ A/cm² was sufficient to achieve deterministic magnetization reversal.
• The SOT efficiency (ξ_DL) was quantitatively measured to be approximately 0.22, exceeding values reported in conventional Pt/ferromagnet systems.
• Harmonic measurements confirmed the high SOT efficiency and provided quantitative validation of the spin-orbit torque mechanism.
• The Fe3GaTe2/Pt heterostructure exhibited stable and reproducible switching behavior over multiple cycles at 300 K.
• The results establish a critical foundation for scalable, low-power spintronic devices based on 2D van der Waals magnets.