Crystal growth, transport, and magnetic properties of Ln3Co4Sn13 (Ln=La, Ce) with a perovskite-like structure

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 Pm3¯n (No. 223) with Z=2Z=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=2.56μB 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.

Ln3Co4Sn13 (Ln  =La, Ce) have been grown in single crystalline form from a Sn flux. Their crystal structures are compared to the A′A3″B4O12-type perovskites. The La compound displays conventional type II superconductivity below Tc=2.8K. Evidence of a heavy fermionic character is seen in the heat capacity data for the Ce compound which has a large enhanced specific heat coefficient at low temperatures.Figure optionsDownload as PowerPoint slide