Magnons in gamma -MnCu

Abstract
Magnons in an antiferromagnetic gamma -MnCu alloy (94 at.% Mn) have been studied at room temperature by inelastic neutron scattering up to an energy of 12 THz. The magnons can be represented by a dispersion relation of the form omega q2=C2q2+ omega 02 with damping Gamma = Gamma 0 omega q. Interpretation of the data on this basis yields values for the spin-wave velocity of C approximately 40 THz AA( approximately 25 km s-1), in general agreement with theory, and energy gap omega 0=1.1+or-0.1 THz.