Imaging and control of critical spin fluctuations in two-dimensional magnets

Abstract

Strong spin fluctuations are expected near the thermodynamic critical point of a continuous magnetic phase transition. Such critical spin fluctuations are highly correlated and in principle can occur at any time- and length-scales; they govern critical phenomena and potentially can drive new phases. Although theoretical studies have been made for decades, direct observation of critical spin fluctuations remains elusive. The recent discovery of two-dimensional (2D) layered magnets, in which spin fluctuations significantly modify magnetic properties as compared to their bulk counterparts and integration into heterostructures and devices can be easily achieved, provides an ideal platform to investigate and harness critical spin phenomena. Here we develop a fast and sensitive magneto-optical imaging microscope to achieve wide-field, real-time monitoring of critical spin fluctuations in single-layer CrBr3, which is a 2D ferromagnetic insulator. We track the critical phenomena directly from the fluctuation correlations and observe both slowing-down dynamics and enhanced correlation length. Through real-time feedback control of critical spin fluctuations, we further achieve switching of magnetic states solely by electrostatic gating without applying a magnetic field or a Joule current. The ability to directly image and control critical spin fluctuations in 2D magnets opens up exciting opportunities to explore critical phenomena and develop applications in nanoscale engines and information science.

References in corpus (13)

• Layer-dependent Ferromagnetism in a van der Waals Crystal down to the Monolayer Limit
• Discovery of intrinsic ferromagnetism in 2D van der Waals crystals
• Gate-tunable Room-temperature Ferromagnetism in Two-dimensional Fe${}_3$GeTe${}_2$
• Magnetic 2D materials and heterostructures
• Electrical Control of 2D Magnetism in Bilayer CrI3
• Giant Tunneling Magnetoresistance in Spin-Filter van der Waals Heterostructures
• Controlling magnetism in 2D CrI3 by electrostatic doping
• Probing magnetism in 2D van der Waals crystalline insulators via electron tunneling
• Stacking-Dependent Magnetism in Bilayer CrI${}_3$
• On the origin of magnetic anisotropy in two dimensional CrI${}_3$
• Interplay between Kitaev interaction and single ion anisotropy in ferromagnetic CrI${}_3$ and CrGeTe${}_3$ monolayers
• Fundamental Spin Interactions Underlying the Magnetic Anisotropy in the Kitaev Ferromagnet CrI${}_3$
• High-throughput Imaging and Spectroscopy of Individual Carbon Nanotubes in Devices with Light Microscopy

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• Spin Dynamics in van der Waals Magnetic Systems
• Spin dynamics slowdown near the antiferromagnetic critical point in atomically thin FePS3
• Progress and Prospects in Two-Dimensional Magnetism of van der Waals Materials
• AC susceptometry of 2D van der Waals magnets enabled by the coherent control of quantum sensors
• Quantum noise spectroscopy of dynamical critical phenomena
• Magnetic order in the computational 2D materials database (C2DB) from high throughput spin spiral calculations
• Analyser-free, intensity-based wide-field magneto-optical microscopy
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• Acousto-magnonic spin Hall effect in honeycomb antiferromagnets
• Enhancing magneto-optic effects in two-dimensional magnets by thin-film interference
• Probing critical spin fluctuations with a composite magnetoelectric method: A case study on a Kitaev spin liquid candidate Na${}_3$Co${}_2$SbO${}_6$
• Electrically tunable room-temperature ferromagnetism in CrBr${}_3$
• Lattice and magnetic structure in the van der Waals antiferromagnet VBr3
• Magnetization dependent tunneling conductance of ferromagnetic barriers
• Wideband covariance magnetometry below the diffraction limit
• Propagating Collective Spin-valley Modes in Twisted WSe2