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arXiv · 1406.3544

$^{119}$Sn-NMR investigations on superconducting Ca$_3$Ir$_4$Sn$_{13}$: Evidence for multigap superconductivity

R. Sarkar·F. Brückner·M. Günther·C. Petrovic·Kefeng Wang·P. K. Biswas·H. Luetkens·E. Morenzoni·A. Amato·H-H. Klauss
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Abstract

We report bulk superconductivity (SC) in Ca$_3$Ir$_4$Sn$_{13}$ by means of $^{119}$Sn nuclear magnetic resonance (NMR) experiments. Two classical signatures of BCS superconductivity in spin-lattice relaxation rate ($1/T_1$), namely the Hebel-Slichter coherence peak just below the $T_c$ and the exponential decay in the superconducting phase, are evident. The noticeable decrease of $^{119}$Sn Knight shift below $T_c$ indicates spin-singlet superconductivity. The temperature dependence of the spin-lattice relaxation rate ($1/T_1$) is convincingly described by the multigap isotropic superconducting gap. Present NMR experiments do not witness any sign of enhanced spin fluctuations in the normal state.

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R. Sarkar, F. Brückner, M. Günther, C. Petrovic, Kefeng Wang, P. K. Biswas, H. Luetkens, E. Morenzoni, A. Amato, H-H. Klauss. 2014-06-13. $^{119}$Sn-NMR investigations on superconducting Ca$_3$Ir$_4$Sn$_{13}$: Evidence for multigap superconductivity. https://doi.org/10.1016/j.physb.2015.09.030

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