Varied magnetic phases in a van der Waals easy-plane antiferromagnet revealed by nitrogen-vacancy center microscopy

Abstract

Interest in van der Waals materials often stems from a desire to miniaturise existing technologies by exploiting their intrinsic layered structure to create near atomically-thin components that do not suffer from surface defects. One appealing property is easily-switchable yet robust magnetic order, a quality only sparsely demonstrated in the case of in-plane anisotropy. In this work, we use widefield nitrogen-vacancy (NV) center magnetic imaging to measure the properties of individual flakes of CuCrP${}_2$S${}_6$, a multiferroic van der Waals magnet known to exhibit weak easy-plane anisotropy in the bulk. We chart the crossover between in-plane ferromagnetism in thin flakes down to the trilayer, and the bulk behaviour dominated by a low-field spin-flop transition. Further, by exploiting the directional dependence of NV center magnetometry, we are able to observe an instance of a predominantly out-of-plane ferromagetic phase near zero field, in contradiction with expectation and previous experiments on the bulk material. We attribute this to the presence of surface anisotropies arising from the sample preparation process or exposure to the ambient environment, which is expected to have more general implications for a broader class of weakly anisotropic van der Waals magnets.

arXiv comment24 pages, 20 figures (including supplementary information)

References in corpus (27)

• 2D materials and van der Waals heterostructures
• Layer-dependent Ferromagnetism in a van der Waals Crystal down to the Monolayer Limit
• Discovery of intrinsic ferromagnetism in 2D van der Waals crystals
• Antiferromagnetic spintronics
• Magnetometry with nitrogen-vacancy defects in diamond
• Controlling magnetism in 2D CrI3 by electrostatic doping
• Probing condensed matter physics with magnetometry based on nitrogen-vacancy centres in diamond
• Probing magnetism in 2D materials at the nanoscale with single spin microscopy
• Magnetic Order and Symmetry in the 2D Semiconductor CrSBr
• Atomically Thin CrCl3: An in-Plane Layered Antiferromagnetic Insulator
• Layered Antiferromagnetism Induces Large Negative Magnetoresistance in the van der Waals Semiconductor CrSBr
• Evolution of interlayer and intralayer magnetism in three atomically thin chromium trihalides
• Giant enhancement of interlayer exchange in an ultrathin 2D magnet
• Intrinsic 2D-XY ferromagnetism in a van der Waals monolayer
• Two-Dimensional Multiferroic Semiconductors with Coexisting Ferroelectricity and Ferromagnetism
• Determining the phase diagram of atomically thin layered antiferromagnet CrCl${}_3$
• In-plane Magnetization Induced Quantum Anomalous Hall Effect
• Electrical and Thermal Generation of Spin Currents by Magnetic Graphene
• Spin properties of dense near-surface ensembles of nitrogen-vacancy centres in diamond
• In-plane magnetic domains and Néel-like domain walls in thin flakes of the room temperature CrTe${}_2$ van der Waals ferromagnet
• Improved current density and magnetisation reconstruction through vector magnetic field measurements
• Imaging domain reversal in an ultrathin van der Waals ferromagnet
• Laser modulation of superconductivity in a cryogenic widefield nitrogen-vacancy microscope
• Characterization of room-temperature in-plane magnetization in thin flakes of CrTe${}_2$ with a single spin magnetometer
• Emergence of electric-field-tunable interfacial ferromagnetism in 2D antiferromagnet heterostructures
• Comparison of different methods of nitrogen-vacancy layer formation in diamond for widefield quantum microscopy
• An Integrated Widefield Probe for Practical Diamond Nitrogen-Vacancy Microscopy

Cited by in corpus (5)

• Untrained physically informed neural network for image reconstruction of magnetic field sources
• Nitrogen-vacancy magnetometry of CrSBr by diamond membrane transfer
• Stray magnetic field imaging of thin exfoliated iron halides flakes
• Self-assembled fluorescent nanodiamond layers for quantum imaging
• Nanodiamond Sensing of Stray Fields during Domain Reversal