P. Chris Hammel (OSU)

Date: Mon. April 21st, 2025, 12:45 pm-1:45 pm
Location: Rockefeller 221 (Foldy Room) & Zoom
Website: https://physics.osu.edu/people/hammel.7
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Quantum Sensing of Broadband Spin Dynamics and Magnon Transport in Antiferromagnets

P. Christ Hammel

Department of Physics, Ohio State University

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Optical detection of magnetic resonance using quantum spin sensors (QSS) provides a spatially local and sensitive technique to probe spin dynamics in magnets.  However, its utility as a probe of antiferromagnetic resonance (AFMR) remains an open question. We report the first experimental demonstration of optically detected AFMR in layered van der Waals antiferromagnets (AF) up to frequencies of 24 GHz. We leverage QSS spin relaxation due to low-frequency magnetic field fluctuations arising from collective dynamics of magnons excited by the uniform AFMR mode. First, through AFMR spectroscopy we characterize the intrinsic exchange fields and magnetic anisotropies of the AF. Second, using the localized sensitivity of the QSS we demonstrate magnon transport over tens of micrometers. Finally, we find that optical detection efficiency increases with increasing frequency. This showcases the dual capabilities of QSS as detectors of high frequency magnetization dynamics and magnon transport, paving the way for understanding and controlling the magnetism of antiferromagnets.

Host: Shulei Zhang