Spin-wave dispersion relations in disordered Fe-V alloys

Abstract

The spin-wave dispersion relations of the ferromagnetic disordered alloys ${\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{V}}_{x}$ ($x=0.076, 0.135, 0.160, \mathrm{and} 0.187$) were studied by means of the inelastic scattering of neutrons. The observed dispersion relations are adequately represented by the power law, $E=D{q}^{2}(1\ensuremath{-}\ensuremath{\beta}{q}^{2})$, in a wide energy range up to 80 meV. The concentration dependence of the exchange stiffness constant $D$ shows good agreement with previous results obtained by means of the small-angle scattering of neutrons and by the analysis of the temperature dependence of the bulk magnetization. The observed results can be explained by the Heisenberg model and, to some extent, by the itinerant-electron model.