Spin-wave dispersion in magnetostrictive Fe-Ga alloys: Inelastic neutron scattering measurements

Abstract

Fe-Ga alloys of appropriate Ga concentration and heat treatment show a very large enhancement in the tetragonal magnetostriction over that of pure $\ensuremath{\alpha}\text{\ensuremath{-}}\mathrm{Fe}$ $[{\ensuremath{\lambda}}_{100}(\mathrm{Fe}\text{\ensuremath{-}}\mathrm{Ga})\ensuremath{\sim}15{\ensuremath{\lambda}}_{100}(\mathrm{Fe})]$. In order to gain further understanding of the extraordinary magnetoelastic characteristics of this system, the spin dynamics of two of these alloys, ${\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Ga}}_{x}$ ($x=0.160$ and 0.225), were studied using inelastic neutron scattering techniques. The correlation of the spin-wave dispersion curve with the lattice constant and atomic radii of solute is examined for this and other Fe alloys.