Single crystals of R3T4Sn13 (R = La, Sr; T = Rh, Ir) are synthesized by a Sn-flux method. Superconducting transition temperatures Tc are determined on the basis of magnetic susceptibility and electrical resistivity measurements. For La3T 4Sn13, Tc = 3.1 and 2.5 K when T = Rh and Ir, respectively; similarly, for Sr3T4Sn13, T c = 4.2 and 5.0 K. Specific heat measurements indicate that superconducting gaps of these compounds are isotropic and that these superconductors can be categorized as strong-coupling superconductors on the basis of the values of ΔCe/γTc and 2Δ(0)/kBTc. The upper critical field shows a clear enhancement with respect to the Werthamer-Helfand-Hohenberg prediction; this enhancement is consistent with the presence of a strong electron-phonon coupling. We summarized the normal and superconducting parameters of R 3T4Sn13 (R = La, Sr; T = Rh, Ir) in Table.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - May 17 2011|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics