Magnetic structure of the UCuxSi2−x system

Neutron powder diffraction experiments were performed on selected compositions of the UCuxSi2−x system exhibiting an interesting magnetic phase diagram towards the composition: spin fluctuation behaviour for x<0.49, ferromagnetism for 0.49≤x<0.80, spin glass state for 0.80antiferromagnetism for 0.92collinear ferromagnetic structure where the uranium magnetic moments equal to 1.1(1) and 2.5(1)μB, respectively, are aligned in the basal plane of the [U6] trigonal prisms. On the contrary, UCu0.96Si1.04 adopts a non-collinear antiferromagnetic structure similar to that observed for UCuSn. Moreover, the study confirms the absence of long range magnetic order for UCu0.90Si1.10.