Spin and charge dynamics of chromium alloys

Both the spin- and charge-density waves of Cr alloys are produced by the Coulomb attraction between electrons and holes on nearly nested Fermi surfaces. Driven by quasiparticle transitions, transverse spin-wave and longitudinal phason modes are associated with the rotational and translational symmetries of pure Cr and its dilute alloys. At low frequencies, both spin and charge phasons have a nearly linear dispersion with a mode velocity which approaches the spin-wave velocity as T approaches T_N or as the mismatch between the Fermi surfaces increases.