MAGNETIC AND ELECTRICAL-PROPERTIES IN UCUSN, UPDIN AND TH-SUBSTITUTED UNISN

High-field magnetization, susceptibility and electrical resistivity were measured for uranium-based compounds UCuSn, UPdIn and U1-xThxNiSn with different crystal structures. UCuSn with the hexagonal CaIn2-type structure is an antiferromagnet with TN = 60 K. The resistivity holds a rather larger value of 0.8 mΩ cm at high temperatures but turns up below TN. UPdIn with the hexagonal Fe2P-type structure is a heavy-electron compound with double magnetic transitions. A c-axis modulated structure, which appears at TN = 21 K, changes into a squaring-up structure along the c-axis below Tc = 8.5 K. At 4.2 K, the M(H) curve up to 36 T reveals a three step metamagnetism for the aligned powder. UNiSn with the cubic MgAgAs-type structure exhibits a semiconductor to metal transition at TN = 45 K, where a type I antiferromagnetic ordering sets in. Th substitution leads to a decrease in TN and prevents the transition to the metallic state. © 1990.