Formation of cubic URh4In and UPd4.5In0.5 phases and their characterization by X-ray-diffraction, magnetic-susceptibility, and electrical-resistivitymeasurements

The ternary phases URh4In and UPd4.5In0.5 are formed and their polycrystall ine samples are found by X-ray diffraction to adopt the cubic AuCu3-type st ructure, with room-temperature lattice parameters of 399.5+/-0.2 and 407.0/-0.5 pm, respectively, similar to the structure and lattice parameters in the related binary phases URh3 and UPd5-x, respectively. Measurements of th e de-magnetic susceptibility show in URh4In a weak temperature dependence a t high temperatures and a rise at lower temperatures, while in UPd4.5In0.5 a Curie-Weiss behaviour (with theta(p) = -84 K and mu(eff) = 3.02 mu(B)) at high temperatures and an antiferromagnetic-like transition at T-max = 18+/ -1 K is observed. The temperature dependence of the electrical resistivity rho(T) of URh4In indicates a metallic character with a BT2.5 dependence at low temperatures. A similar character of rho(T) at high temperatures is exh ibited also by UPd4.5In0.5. However, the latter exhibits a different low-te mperature behaviour, involving a small maximum in the resistivity just belo w T-max, the size of this maximum being reduced under applied magnetic fiel d. (C) 2000 Elsevier Science S.A. All rights reserved.