Magnetic scattering in irradiated MnCu4

Abstract

There have been many neutron-scattering studiesof short-range order in Cu_Mn alloys which show a diffuse (1�) peak. It has been suggested that this may be a precursor of long-range order in the alloys. Atomic short-range order in Cu_Mn alloys is strongly associated with effects on the magnetic properties of the samples. Irradiating a sample of Mn20Cu80 in a high fast-neutron flux has produced small superlattice Bragg peaks on top of a slightly sharpened (1�) diffuse peak, indicating the development of long-range atomic order. We report the quasi-elastic magnetic diffuse scattering between scattering vectors of 0.16 and 2.5 ŭ1, which shows no measurable change associated with this long-range atomic order.