Crystal structure and physical properties of NpPd2Sn

A new compound NpPd2Sn was prepared and studied by means of X-ray diffraction, magnetization, electrical resistivity and heat capacity measurements. Its crystal structure was refined from the single-crystal X-ray data and shown to be orthorhombic of the UPd2Sn-type (s.g. Pnma). The compound orders antiferromagnetically at TN=15K. All the bulk properties show temperature variations characteristic of systems with strong electronic correlations, with a large negative paramagnetic Curie temperature (θCW=-80K), a negative logarithmic slope of the resistivity (cK=-11μΩcm/K) and a strongly enhanced electronic specific heat (γ=400mJ/molK2). Thus NpPd2Sn may be a novel heavy-fermion system, one of very few known so far amidst Np-based intermetallics