Probing GHz Spin Dynamics Across Magnetic Phase Transitions in CrCl3 Nanoflakes Using Nitrogen-Vacancy Microscopy

Abstract

CrCl3, a layered van der Waals (vdW) magnet, exhibits in-plane magnetic anisotropy and enhanced interlayer coupling upon stacking, making it an ideal platform to host exotic nanoscale magnetic phenomena such as magnon hydrodynamics and meron-like topological spin defects. When interfaced with other vdW materials, its antiferromagnetic-to-ferromagnetic and ferromagnetic-to-paramagnetic phase transitions and magnetic anisotropy can be tuned by voltage, strain, and layer stacking. Understanding the spin dynamics of CrCl3 at its magnetic phase transitions is crucial to its applications in magnonics. Here, we investigate the spin dynamics of CrCl3 nanoflakes using cryogenic diamond quantum sensing microscopy, based on measuring optically detected magnetic resonance, Rabi oscillations, and spin-lattice relaxation time (T1) of shallow nitrogen vacancy (NV) centers in diamond. In the ferromagnetic regime, we observe a pronounced reduction in the NV spin resonance contrast, a collapse of the Rabi oscillations, and a strong enhancement by two orders of magnitude of the relaxation rate G1 = 1/T1. These observations indicate intensified spin fluctuations in the gigahertz range. Broadband ferromagnetic resonance spectroscopy on CrCl3 crystals reveals resonance frequencies in the 4-15 GHz range together with a linewidth of ~24 mT, further supporting the NV measurements. A phenomenological model of magnetic-noise-induced NV relaxation reproduces the temperature dependence of G1 by combining antiferromagnetic, ferromagnetic, and paramagnetic fluctuation channels, indicating that magnetic noise is strongest in the ferromagnetic regime and evolves markedly across the phase transition. These results are crucial for using CrCl3 in 2D magnonics and hybrid quantum-magnon systems.

References in corpus (22)

• Tutorial: A Beginner's Guide to Interpreting Magnetic Susceptibility Data with the Curie-Weiss Law
• Probing magnetism in 2D materials at the nanoscale with single spin microscopy
• Atomically Thin CrCl3: An in-Plane Layered Antiferromagnetic Insulator
• Tracking Temperature Dependent Relaxation Times of Individual Ferritin Nanomagnets with a Wide-band Quantum Spectrometer
• Electron spin resonance and ferromagnetic resonance spectroscopy in the high-field phase of the van der Waals magnet CrCl${}_3$
• Anisotropic magnetocaloric effect and critical behavior in CrCl${}_3$
• Magnon-mediated qubit coupling determined via dissipation measurements
• Massless Dirac magnons in the two dimensional van der Waals honeycomb magnet CrCl3
• Gapless Dirac magnons in CrCl${}_3$
• AC susceptometry of 2D van der Waals magnets enabled by the coherent control of quantum sensors
• Nitrogen-vacancy magnetometry of individual Fe-triazole spin crossover nanorods
• Physical Vapor Transport Growth of Antiferromagnetic CrCl${}_3$ Flakes Down to Monolayer Thickness
• Mapping of Spin-Wave Transport in Thulium Iron Garnet Thin Films Using Diamond Quantum Microscopy
• Nitrogen-Vacancy Magnetic Relaxometry of Nanoclustered Cytochrome C Proteins
• Proposal to detect emergent gauge field and its Meissner effect in spin liquids using NV Centers
• Quantum Sensing of Broadband Spin Dynamics and Magnon Transport in Antiferromagnets
• Time-resolved diamond magnetic microscopy of superparamagnetic iron-oxide nanoparticles
• Magnetic Relaxometry of Methemoglobin by Widefield Nitrogen-Vacancy Microscopy
• Imaging Local Effects of Voltage and Boron Doping on Spin Reversal in Antiferromagnetic Magnetoelectric Cr2O3 Thin Films and Devices
• Room temperature relaxometry of single nitrogen-vacancy centers in proximity to $\alpha$-RuCl${}_3$ nanoflakes
• Effect of Substrate on Spin-Wave Propagation Properties in Ferrimagnetic Thulium Iron Garnet Thin Films
• Nitrogen-Vacancy Magnetometry of Edge Magnetism in WS2 Flakes