Probing the magnetic ground state of single crystalline Ce 3 TiSb 5

Motivated by the report of superconductivity in R 3 TiSb 5 (R = La and Ce) and possibly Nd 3 TiSb 5 at ∼4 K, we grew single crystals of La 3 TiSb 5 and Ce 3 TiSb 5 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 Ce 3 TiSb 5 , crystallizing in a hexagonal P 6 3 / mcm structure, were studied in detail. We find that the Ce ions in Ce 3 TiSb 5 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 K 2 . 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 4 f -electron heat capacity of Ce 3 TiSb 5 was reproduced fairly well by the energy levels derived from the CEF analysis.