LNS: Laboratory for Neutron Scattering and Imaging

Magnetic topological phases of quantum matter are an emerging frontier in physics and material science. Along these lines, several kagome magnets have appeared as the most promising platforms. Here, we explore magnetic correlations in the kagome magnet Co₃Sn₂S₂. Using muon spin-rotation, we present evidence for competing magnetic orders in the kagome lattice of this compound.

We investigate the Sn composition dependence of the Yb valence and local magnetization in YbMn₆Ge_6−xSn_x (4.25 􏰁≤x≤ 5.80) using x-ray absorption spectroscopy (XANES) and x-ray magnetic circular dichroism at the Yb L₃ edge. In these materials, where Mn is ferromagnetically ordered, we observe a decrease of the Yb valence upon reducing the chemical pressure by Sn doping and a suppression of the Yb magnetic moment for strongly hybridized  4f states (ν ∼ 2.77).

We report the discovery of topological magnetism in the candidate magnetic Weyl semimetal CeAlGe. Using neutron scattering we find this system to host several incommensurate, square-coordinated multi-k⃗ magnetic phases below T_N. The topological properties of a phase stable at intermediate magnetic fields parallel to the c axis are suggested by observation of a topological Hall effect.