Neutron Diffraction Studies of Dilute Cr-Re Single Crystal Alloys

Neutron diffraction studies have been performed on five Cr-Re single crystal alloys with a Re content from 0 to 0·8 at. %. It was found that the wave vector of the sinusoidally modulated spin arrangement increases uniformly with temperature and concentration until a critical value of about 0·97. (2π/a) when it changes abruptly to 2π/a. This agrees with earlier experiments on Cr-Mn alloys. For dilute Cr alloys there is thus no essential difference between the addition of 5d-electrons and 3d-electrons. It was furthermore found that the most dilute alloys undergo a first order transition at the Néel temperature in agreement with earlier observations on pure Cr. Due to experimental difficulties the order of the transition at the Néel temperature cannot be determined unambiguously for the more concentrated alloys.