Magnetic field tuning of dynamic spin orbit effects in a honeycomb magnet

This is a continuation proposal to probe the magnetic excitations in a Fe-based stacked honeycomb magnet in applied magnetic field. In recent zero-field LET measurements we observed evidence for strong spin-orbit effects manifested in anomalous intensity modulations at low energies attributed to a mixed spin-orbital character of the magnetic moments and gap openings, both at the inter-layer zone boundary and also where Dirac magnon cones are present at the corners of the in-plane hexagonal Brillouin zone. Here we propose to measure the excitations as a function of applied field that drive a transition above 8 T to a phase where the ground-state spin-orbital admixture changes, in order to further probe the spin-orbit effects on the cooperative dynamics and constrain the exchange Hamiltonian.