Stractural and Magnetic Phase Transitions in a New Heavy-Fermion Compound UPd2In

Abstract
Structural, magnetic, transport and thermal properties of UPd 2 In with a Heusler-type structure have been investigated. The temperature variations of thermal expansion and of X-ray diffraction pattern indicate a first-order structural transition at T s ≃180 K. The significant change in both the magnetic susceptibility and thermoelectric power near T s indicates that the uranium 5 f electrons play an important role in the structural transition. This compound undergoes an antiferromagnetic ordering at 20 K. The extrapolated value of C / T , specific heat divided by temperature, is 0.20 J/K 2 mol at 0 K; thus UPd 2 In is an antiferromagnetic heavy-fermion compound