Nodeless superconductivity in the cage-type superconductor Sc5Ru6Sn18 with preserved time-reversal symmetry. (16th July 2018)

• Record Type: Journal Article
• Authors: Kumar, D; Kuo, C N; Astuti, F; Shang, T; Lee, M K; Lue, C S; Watanabe, I; Barker, J A T; Shiroka, T; Chang, L J
• Is Part Of: Journal of physics. Volume 30:Number 31(2018)
• Publication Date: 2018-07-16
• Subjects: superconductivity -- muon-spin relaxation -- time reversal symmetry; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aacf65
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: We report the single-crystal synthesis and detailed investigations of the cage-type superconductor Sc5 Ru6 Sn18, using powder x-ray diffraction (XRD), magnetization, specific-heat and muon-spin relaxation ( µ SR) measurements. Sc5 Ru6 Sn18 crystallizes in a tetragonal structure (space group I 41 / acd ) with lattice parameters a = 1.387(3) nm and c = 2.641(5) nm. Both DC and AC magnetization measurements prove the type-II superconductivity in Sc5 Ru6 Sn18 with T c ≈ 3.5(1) K, a lower critical field = 157(9) Oe and an upper critical field, = 26(1) kOe. The zero-field electronic specific-heat data are well fitted using a single-gap BCS model, with = 0.64(1) meV. The Sommerfeld constant γ varies linearly with the applied magnetic field, indicating s -wave superconductivity in Sc5 Ru6 Sn18 . Specific-heat and transverse-field (TF) µ SR measurements reveal that Sc5 Ru6 Sn18 is a superconductor with strong electron–phonon coupling, with TF- µ SR also suggesting a single-gap s -wave character of the superconductivity. Furthermore, zero-field µ SR measurements do not detect spontaneous magnetic fields below T c, hence implying that time-reversal symmetry is preserved in Sc5 Ru6 Sn18 .