Matin M, Kulkarni R, Thamizhavel A, Dhar S K, Provino A, Manfrinetti P
Department of Condensed Matter Physics & Materials Science, Tata Institute of Fundamental Research, Mumbai-400005, India.
J Phys Condens Matter. 2017 Apr 12;29(14):145601. doi: 10.1088/1361-648X/aa57c0. Epub 2017 Feb 27.
Motivated by the report of superconductivity in RTiSb (R = La and Ce) and possibly NdTiSb at ∼4 K, we grew single crystals of LaTiSb and CeTiSb 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 CeTiSb, crystallizing in a hexagonal P6/mcm structure, were studied in detail. We find that the Ce ions in CeTiSb 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. 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 CeTiSb was reproduced fairly well by the energy levels derived from the CEF analysis.
受RTiSb（R = La和Ce）以及可能的NdTiSb在约4 K时超导性报告的启发，我们采用以Sn为助熔剂的高温溶液法生长了LaTiSb和CeTiSb单晶。虽然在这两种化合物中，我们都观察到电阻率和低场磁化强度在3.7 K时出现超导转变，但我们的数据确凿地表明，这是由单晶中残留的Sn助熔剂引起的。特别是，热容数据并未呈现出体超导转变所预期的任何异常。我们详细研究了结晶为六方P6/mcm结构的CeTiSb的各向异性磁性能。我们发现，CeTiSb中的Ce离子形成了一个近藤晶格，并在5.5 K时表现出反铁磁有序，其磁矩减小，索末菲系数适度归一化，为598 mJ/mol K。发现特征单离子近藤能级约为8 K。对磁化数据进行了晶体电场（CEF）分析。通过CEF分析得出的能级相当好地再现了CeTiSb的4f电子热容中实验观察到的肖特基峰。
