Speaker
Description
Co3Sn2S2 is a prototypical magnetic kagome Weyl semimetal in which broken time-reversal symmetry, strong spin–orbit coupling, and kagome-derived electronic structure generate a large Berry-curvature-driven response, resulting in an unusually large intrinsic anomalous Hall conductivity [1]. Since the Weyl-node configuration and the associated Berry curvature depend sensitively on the magnetic state, a microscopic understanding of the magnetism is essential [2].
Here, we show using pulsed-field x-ray magnetic circular dichroism (XMCD), bulk magnetometry, and inelastic neutron scattering that Co3Sn2S2 exhibits exceptionally large magnetocrystalline anisotropy despite the largely quenched Co orbital moment. This suggests that the anisotropy cannot be explained within a simple single-ion picture alone, but may instead reflect the combined effect of kagome-derived bands near the Fermi level, Co-Sn hybridization, and the stronger spin-orbit coupling of Sn. Element-specific XMCD further reveals a small antiparallel Sn moment, consistent with DFT and indicative of weak ferrimagnetism, likely originating from Co-Sn hybridization. In addition, scanning transmission x-ray microscopy shows that anomalous discontinuities in field-history-dependent magnetization originate from rapid domain nucleation followed by domain evolution. Our results establish microscopic constraints on the magnetic state of Co3Sn2S2, which are essential for understanding the stability of its Weyl phase and the origin of its large anomalous Hall effect.