UC Irvine

Ln3Co4Sn13 (Ln=La, Ce) have been synthesized by flux growth and characterized by single crystal X-ray diffraction. These compounds adopt the Yb3Rh4Sn13-type structure and crystallize in the cubic space group Pm over(3, -) n (No. 223) with Z = 2. Lattice parameters at 298 K are a = 9.6430 ( 6 ) Å, V = 896.68 ( 10 ) Å3, and a = 9.6022 ( 5 ) Å, V = 885.34 ( 8 ) Å3 for the La and Ce analogues, respectively. The crystal structure consists of an Sn-centered icosahedron at the origin of the unit cell, which shares faces with eight Co trigonal prisms and 12 Ln-centered cuboctahedra. Magnetization data at 0.1 T show paramagnetic behavior down to 1.8 K for Ce3Co4Sn13, with μeff = 2.56 μB per Ce3+, while conventional type II superconductivity appears below 2.85 K in the La compound. Electrical resistivity and specific heat data for the La compound show a corresponding sharp superconducting transition at Tc∼2.85 K. The entropy and resistivity data for Ce3Co4Sn13 show the existence of the Kondo effect with a complicated semiconducting-like behavior in the resistivity data. In addition, a large enhanced specific heat coefficient at low T with a low magnetic transition temperature suggests a heavy-fermionic character for the Ce compound. Herein, the structure and physical properties of Ln3Co4Sn13 (Ln=La, Ce) are discussed. © 2006 Elsevier Inc. All rights reserved.