Revealing complementing non-collinear orbital magnetic moment of a magnon

Magnons are bosonic quasiparticles and are the quanta of magnetic oscillations of systems with periodically ordered magnetic moments. It has been assumed so far that the magnetic moment carried by magnons is composed of only a spin magnetic moment as the spin texture defines the directions relative to which a deviation can occur. Recent work proposed that magnons can carry a complementing non-collinear orbital magnetic moment brought about by spin-orbit coupling or dipolar interactions in addition to its spin magnetic moment. The magnitude of the orbital magnetic moment depends on the details of the system, but first estimations predict that it could be as large as 0.2μB in Yttrium Iron Garnet (YIG). The aim of this proposal is to confirm the presence of an orbital magnetic moment component associated with magnons in YIG by measuring magnetic linear dichroism at magnon excitations using the ultra-high-precision Fe 2p3d resonant inelastic X-ray scattering available at ID32 beamline.