Probing the magnetic ground state of single crystalline Ce₃TiSb₅

Motivated by the report of superconductivity in R₃TiSb₅ (R  =  La and Ce) and possibly Nd₃TiSb₅ at  ∼4 K, we grew single crystals of La₃TiSb₅ and Ce₃TiSb₅ by the high-temperature solution method using Sn as a flux. While in both compounds we observed a superconducting transition at 3.7 K for resistivity and low-field magnetization, our data conclusively show that it arose from residual Sn flux present in the single crystals. In particular, the heat capacity data do not present any of the anomalies expected from a bulk superconducting transition. The anisotropic magnetic properties of Ce₃TiSb₅, crystallizing in a hexagonal P6₃/mcm structure, were studied in detail. We find that the Ce ions in Ce₃TiSb₅ form a Kondo lattice and exhibited antiferromagnetic ordering at 5.5 K with a reduced moment and a moderately normalized Sommerfeld coefficient of 598 mJ/mol K². The characteristic single-ion Kondo energy scale was found to be  ∼8 K. The magnetization data were subjected to a crystal electric field (CEF) analysis. The experimentally observed Schottky peak in the 4f-electron heat capacity of Ce₃TiSb₅ was reproduced fairly well by the energy levels derived from the CEF analysis.