Inelastic neutron scattering experiments have been performed on a single crystal of Sendust (${\mathrm{Fe}}_{2.94}$${\mathrm{Al}}_{0.38}$${\mathrm{Si}}_{0.68}$) in order to study the spin dynamics below and above the ferromagnetic Curie temperature $T_C$=794±1 K. Below $T_C$, clear ferromagnetic spin waves are observed up to the energy transfer of about 60 meV. The resulting dispersion relation and line broadenings are compared with theoretical models. Above $T_C$, paramagnetic scattering is observed with the energy width Γ varying like $q^{2.5}$.

• Received 23 September 1987

DOI:https://doi.org/10.1103/PhysRevB.37.7175