Pseudo-Goldstone Magnons in the Frustrated S=3/2 Heisenberg Helimagnet ZnCr2Se4 with a Pyrochlore Magnetic Sublattice

Wave excitations (magnons) along the helical arrangement of magnetic moments in helimagnets generally travel along this helix, while orthogonal magnons are thought to require much higher energy. New experiments reveal the existence of low-energy orthogonal magnons that could lead to a new understanding of a broad class of magnetic materials.