Bilayer

Quantum mechanics

Anisotropy

Magnetic field

Magnetization

Materials science

Ferromagnetism

Biochemistry

Molecule

Magnetism

Physics

Nanotechnology

Membrane

Magnetoresistance

Magnetocrystalline anisotropy

van der Waals force

Condensed matter physics

Monolayer

Curie temperature

Chemistry

Hall effect

Magnetic anisotropy

Spintronics

Nano Letters

Realization of ferromagnetism in the two-dimensional (2D) van der Waals (vdW) crystals opens up a vital route to understand the magnetic ordering in the 2D limit and to design novel spintronics. Here, we report enriched layer-number-dependent magnetotransport properties in the vdW ferromagnet Fe5GeTe2. By studying the magnetoresistance and anomalous Hall effect (AHE) in nanoflakes with thicknesses down to monolayer, we demonstrate that while the bulk crystals exhibit soft ferromagnetism with an in-plane magnetic anisotropy, hard ferromagnetism develops upon thinning, and a perpendicular easy-axis anisotropy is realized in bilayer flakes, which is accompanied by a pronounced enhancement of AHE because of extrinsic mechanisms. For the monolayer flakes, the hard ferromagnetism is replaced by spin-glass-like behavior, in accordance with the localization effect in the 2D limit. Our results highlight the thickness-based tunability of the magnetotransport properties in the atomically thin vdW magnets that promises engineering of high-performance spintronic devices.

Layer-Number-Dependent Magnetism and Anomalous Hall Effect in van der Waals Ferromagnet Fe<sub>5</sub>GeTe<sub>2</sub>

Layer-Number-Dependent Magnetism and Anomalous Hall Effect in van der Waals Ferromagnet Fe5GeTe2

Layer-Number-Dependent Magnetism and Anomalous Hall Effect in van der Waals Ferromagnet Fe₅GeTe₂