Crystal Growth and Crystal Structure of EuPtIn₄

A single crystal of the indium-rich intermetallic compound EuPtIn4 has been grown by a high-temperature solution growth method, with molten indium as solvent. The crystal structure of the compound was solved from the single crystal X-ray diffraction data and it is found that EuPtIn4 crystallizes in the orthorhombic crystal structure with the space group Cmcm. The estimated lattice constants are a = 4.5300(7) angstrom, b = 16.904(3) angstrom, and c = 7.3601(12) angstrom with the unit cell volume V = 563.60(15) angstrom(3). There are four formula units per unit cell (Z = 4), and the R-parameters are R = 0.0390 and wR(2) = 0.1033 for 496 unique reflections. A comparison of lattice constants with those of isostructural SrPtIn4, LaPtIn4, EuPtIn4, and eYbPtIn(4) indicates that the radius of the rare-earth ion decides the indium octahedra distortion in the bc-plane. This leads to nonmonotonic variation in b and c parameters from the early to the late rare earth element based compounds. EuPtIn4 is a highly conducting material, with a room temperature resistivity of 25 mu Omega.cm. Low-temperature resistivity, magnetization, and heat capacity measurements show two antiferromagnetic transitions near 13 and 5.5 K. From the heat capacity data it was observed that EuPtIn4 has a large Sommerfeld coefficient (gamma), which was estimated to be 725 mJ/K-2.mol