Dynamic critical fluctuations in magnetic materials encode important information about magnetic ordering in the associated critical exponents. Using nitrogen-vacancy centers in diamond, we implement T2 (spin-decoherence) noise magnetometry to study critical dynamics in a 2D Van der Waals magnet CrSBr. By analyzing NV decoherence on time scales approaching the characteristic correlation time τc of critical fluctuations, we extract the critical exponent ν for the correlation length. Our result deviates from the Ising prediction and highlights the role of long-range dipolar interactions in 2D CrSBr. Furthermore, analyzing the divergence of the correlation length suggests the possibility of 2D-XY criticality in CrSBr in a temperature window near TC where static magnetic domains are absent. Our work provides a first demonstration of T2 noise magnetometry to quantitatively analyze critical scaling behavior in 2D materials.
@article{arxiv.2407.05614,
title = {Quantum Noise Spectroscopy of Criticality in an Atomically Thin Magnet},
author = {Mark E. Ziffer and Francisco Machado and Benedikt Ursprung and Artur Lozovoi and Aya Batoul Tazi and Zhiyang Yuan and Michael E. Ziebel and Tom Delord and Nanyu Zeng and Evan Telford and Daniel G. Chica and Dane W. deQuilettes and Xiaoyang Zhu and James C. Hone and Kenneth L. Shepard and Xavier Roy and Nathalie P. de Leon and Emily J. Davis and Shubhayu Chatterjee and Carlos A. Meriles and Jonathan S. Owen and P. James Schuck and Abhay N. Pasupathy},
journal= {arXiv preprint arXiv:2407.05614},
year = {2024}
}
Comments
19 pages main text, 4 main text figures, 26 pages Supplementary Materials, 13 Supplementary figures