Peter A. Fedders, R.L. Melcher
Physical Review B
The implications of magnetic symmetry on the spin-wave spectrum of ferromagnets are examined. Contrary to the usual result, the spin-wave dispersion relation is found to contain a term linear in the wave vector for a definite set of magnetic symmetries. This linear dispersion is shown to be a consequence of antisymmetric exchange. © 1973 The American Physical Society.