Probing magnetism in 2D materials at the nanoscale with single spin microscopy

Abstract

The recent discovery of ferromagnetism in 2D van der Waals (vdw) crystals has generated widespread interest, owing to their potential for fundamental and applied research. Advancing the understanding and applications of vdw magnets requires methods to quantitatively probe their magnetic properties on the nanoscale. Here, we report the study of atomically thin crystals of the vdw magnet CrI${}_3$ down to individual monolayers using scanning single-spin magnetometry, and demonstrate quantitative, nanoscale imaging of magnetisation, localised defects and magnetic domains. We determine the magnetisation of CrI${}_3$ monolayers to be $\approx 16{\mu }_B/$nm${}^2$ and find comparable values in samples with odd numbers of layers, whereas the magnetisation vanishes when the number of layers is even. We also establish that this inscrutable even-odd effect is intimately connected to the material structure, and that structural modifications can induce switching between ferro- and anti-ferromagnetic interlayer ordering. Besides revealing new aspects of magnetism in atomically thin CrI${}_3$ crystals, these results demonstrate the power of single-spin scanning magnetometry for the study of magnetism in 2D vdw magnets.

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References in corpus (3)

• Probing magnetism in 2D materials at the nanoscale with single spin microscopy
• The nature of domain walls in ultrathin ferromagnets revealed by scanning nanomagnetometry
• Gate-controllable magneto-optic Kerr effect in layered collinear antiferromagnets

Cited by in corpus (8)

• Magnetic 2D materials and heterostructures
• Probing magnetism in 2D materials at the nanoscale with single spin microscopy
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• Coexistence of Magnetic Orders in Two-Dimensional Magnet CrI${}_3$
• SQUID-on-tip with single-electron spin sensitivity for high-field and ultra-low temperature nanomagnetic imaging
• Magnetic polaron and antiferro-ferromagnetic transition in doped bilayer CrI${}_3$
• (111)-oriented, single crystal diamond tips for nanoscale scanning probe imaging of out-of-plane magnetic fields
• Single crystal diamond pyramids for applications in nanoscale quantum sensing