U3Pt12Si4: Structural and physical properties of a new uranium-platinum-silicon ternary compound

International audienceA novel ternary compound, namely U3Pt12Si4, which is best described by the crystallographic formula U3Pt12+x-ySi4-x-z (x = 0.15, y = 0.23, z = 0.16), has been discovered in the U-Pt-Si phase diagram. It crystallizes in a hexagonal unit cell (P63/mmc space group) with a = 8.7267(1) Å and c = 9.3385(2) Å. Its structure is an ordered variant of the EuMg5.2 type with partial occupancies of the Si 4e and Pt 2b positions and mixed Si/Pt occupancy of the 6g site. Magnetic properties measurements revealed that the compound is a Curie-Weiss paramagnet with an effective magnetic moment μeff = 3.18 μB. Its low temperature specific heat is moderately enhanced (its Sommerfeld coefficient γ is equal to 79(1) mJ molU- 1 K-2) and the electrical resistivity exhibits some characteristic features of dense Kondo lattices. © 2017 Trans Tech Publications, Switzerland