MAGNETIC AND TRANSPORT-PROPERTIES OF THE UTSN SERIES (T = CO, NI, RU, RH, PD, IR AND PT)

Magnetic susceptibility and electrical resistivity were measured for a series of intermetallic, ternary compounds UTSn, where T stands for Co, Ni, Ru, Rh, Pd, Ir and Pt. For the first time it was shown that UNiSn, except for the well-known cubic MgAgAs-type (low temperature) form, crystallizes also in the orthorhombic CeCu2-type (high temperature) form, which probably exhibits the antiferromagnetic properties below 21 K and has a metallic character of conductivity. Also the off-stoichiometric UPt0.9Sn1.1 alloy was found to have two polymorphic forms, where the low temperature form is the MgAgAs-type and shows the complex magnetic properties at low temperatures, while the high temperature one is the Fe2P-type, which is ferromagnetic below 28 K. For the remaining UTSn compounds we discuss the differences occurring between our and other authors' findings. Especially we emphasize the presence of two magnetic transitions in URhSn; the ferromagnetic one at 17 K and the probably antiferromagnetic one at 52 K. Moreover, two phase transitions of antiferromagnetic character with close lying transition temperatures were found for UPdSn. The obtained experimental results which we analyzed in terms of different crystal structures and the degree of 5f-ligand hybridization which are the main factors influencing the magnetic and transport properties of considered UTSn compounds.