The symmetry properties of the spin-wave dispersion relations of a ferromagnetic metal

Abstract

The magnetic space group of each of the common ferromagnetic metal structures is given and the magnetic little group is identified for the various points and lines of symmetry of the Brillouin zone. By studying the transformation properties of the appropriate spin-wave creation operators the symmetries and degeneracies of the spin waves all over the Brillouin zone have been determined in terms of the irreducible corepresentations of these magnetic little groups. An error has been noted in a previous discussion by Brinkman of spin-wave symmetries in ferromagnetic hexagonal close-packed metals