PREPARATION AND ELECTRICAL-RESISTIVITY OF (PU1-XUX)SB AND (PU1-XYX)SBSINGLE-CRYSTALS

Single crystals of (Pu1-xUx)Sb (with x=0.25, 0.5 and 0.75) and (Pu1-xY x)Sb (with x=0.05, 0.1, 0.4, 0.6, 0.75 and 0.85) were prepared by mine ralization and encapsulated for resistivity measurements down to 1.5 K . Resistivity of Pu0.75U0.25Sb shows two anomalies at 96 and 56 K sugg esting two magnetic transitions, respectively, of antiferromagnetic an d ferromagnetic type. Pu0.5U0.5Sb displays a more complex behavior. A first transition is observed around 155 K, followed by a sharp maximum at 120 K and a second anomaly around 35 K. Pu1-xYxSb measured samples show a logarithmic increase of the resistivity with decreasing temper ature, suggesting a Kondo behavior. For x=0.4 and 0.6 two magnetic tra nsitions are deduced at 36/20 K and 24/7 K, respectively, and for x=0. 75 only one transition is seen around 14 K. (C) 1998 Elsevier Science S.A.