2022/12/06 by Yue Sun, J. Orenstein, Sun, Yue +1
Engineering · Physics and Astronomy · #FOS: Physical sciences #Magnetic Field Sensors Techniques #Magnetic properties of thin films #Physics of Superconductivity and Magnetism #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.2212.03261
openalex publication_date 2022/12/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Antiferromagnets are attractive platforms for the propagation of information via spin waves, offering advantages over ferromagnets in speed of response and immunity to external fields. A recent study of the quasi-2D antiferromagnet CrSBr reported that spin wavepackets propagate with group velocities that are orders of magnitude higher than expected from the magnon dispersion obtained by inelastic neutron scattering [1,2]. Here we show that the anomalous magnitude and anisotropy of the group velocity, vg, are naturally explained by considering the long-range magnetic dipole-dipole interaction. We also demonstrate that vg can be tuned over orders of magnitude by applying an external magnetic field or varying the sample thickness. Beyond spin wavepacket propagation, the dipolar interaction creates the possibility of non-equilibrium Bose-Einstein condensation in antiferromagnets, previously thought to be a property unique to ferromagnets.