MAGNETIC-PROPERTIES OF THE BINARY URANIUM STANNIDES

The structural chemistry and magnetic properties of the binary uranium stannides have been reinvestigated. Together with the well defined tr istannide USn3 (AuCu3 type), the formation of all the recently reporte d binary uranium stannides is confirmed: U3Sn7 (Ce3Sn7 type), USn2 (Zr Ga2 type), USn (ThIn type) and U5Sn4 (Ti5Ga4 type) and magnetic studie s of these latter compounds have been carried out for the first time. USn3 is a spin fluctuating system and all the other binaries order mag netically at low temperature. U3Sn7 and USn2 are antiferromagnets with T-N = 50 K and 75 K and USn and U5Sn4 exhibit ferromagnetic ordering below T-C = 55 K and 65 K respectively. An interesting feature is that in each of these last two compounds, one of the uranium sublattices i s characterized by very short uranium-uranium distances of 3.11 Angstr om which lies far below the Hill limit. (C) 1998 Elsevier Science Ltd. All rights reserved.