Neutron-polarization-analysis study of the spin structure of Cu-Mn spin-glasses

Abstract

Neutron-polarization-analysis measurements as well as unpolarized neutron measurements were made of the diffuse scattering from single-crystal Cu-Mn alloys to determine the atomic and spin pair correlations for this spin-glass system. The results show the presence of a spin modulation with a period that varies continuously in terms of the edge of the fcc crystal cell from $6a_0$ at 5 at.% Mn to about $3a_0$ 25 at.% Mn. The correlation length associated with this modulation is about $6a_0$ at all concentrations. Coexistent with these large modulated regions are smaller regions in which the spin correlations are determined by the atomic short-range order and which have net ferromagnetic moments. The interactions between these ferromagnetic and modulated regions are undoubtedly an essential element in understanding the complicated magnetic behavior of this spin-glass system.