Specific Heatof the Filled Skutterudite [-3pt]Superconductor LaOs4As12

J. Juraszek, Z. Henkie and T. Cichorek Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław, Poland

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We investigated low-temperature specific heat of the filled skutterudite compound LaOs4As12 with a transition temperature Tc=3.2 K. A moderate size of a specific-heat jump points at a weak electron-phonon coupling in this material. At Tc, the electronic contribution to the specific heat was found to be at variance with the predictions for an s-wave superconductor with one energy gap. Additionally, we observed an upward curvature of the upper critical field near the transition temperature. Both features provide some indications towards multiband superconductivity, although anisotropy effects as a viable cause of the observed anomalies in LaOs4As12 cannot be excluded. Similarities to a probable two-band superconductor LaRu4As12 are discussed.

DOI: 10.12693/APhysPolA.130.597 PACS numbers: 74.25.Bt, 74.70.Dd