Quantum Sensing of Broadband Spin Dynamics and Magnon Transport in Antiferromagnets

Quantum sensing enables spatially localized, broadband detection of spin dynamics and magnon transport in antiferromagnets, addressing a key limitation of conventional magnetic resonance techniques

• Demonstrated optically detected antiferromagnetic resonance (ODAFMR) using NV center quantum spin sensors in vdW antiferromagnets (CrCl₃, CrSBr), extending detection up to 24 GHz, well beyond the intrinsic sensor resonance.

• Established that magnon mediated magnetic field fluctuations enable indirect detection of high frequency AFMR modes through enhanced NV spin relaxation, overcoming spectral mismatch limitations.

• Quantitatively extracted exchange fields and magnetic anisotropies from ODAFMR spectra, showing strong agreement with conventional inductive measurements while providing local sensitivity.

• Revealed long range magnon transport over tens of micrometers, indicating low magnon scattering and strong potential for antiferromagnetic spin transport applications.