title: Observation of superconductivity in the intermetallic compound β-IrSn4.
abstract: Low-temperature dc-magnetization, ac electrical resistivity and specific heat measurements were performed on single crystals of the intermetallic compound β-IrSn4. The compound crystallizes in the tetragonal MoSn4-type structure (space group I41/acd) and exhibits superconductivity below Tc = 0.9 ± 0.05 K. Further, the magnitude of the ratios ΔCp/(γnkBTc) = 1.29, 2Δ/(kBTc) = 3.55 and of the electron-phonon coupling λ[overline](e-ph) = 0.5 imply that superconductivity in β-IrSn4 can be ascribed to a s-wave weak coupling regime. We determined crucial thermodynamic characteristics of the superconducting state. It turned out that depending on the assumption of either a spherical or non-spherical Fermi surface, the superconductivity can be ascribed to either a type-I and type-II/1 or type-II in clean limit, respectively. However, the behavior of the upper critical field and the anisotropic crystalline structure of the studied compound provide strong support to the type-II superconductivity. In the normal state the resistivity exhibits a prominent quadratic temperature dependence, which together with a large Kadowaki-Woods ratio and with the enhanced effective mass indicate that the electrons in β-IrSn4 are strongly correlated.
authors.affiliation: Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PO Box 1410, 50-950 Wrocław, Poland. V.H.Tran@int.pan.wroc.pl
authors.forename: Vinh Hung
authors.initials: VH
authors.lastname: Tran
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Bukowski
authors.forename: Piotr
authors.initials: P
authors.lastname: Wiśniewski
authors.forename: Lan Maria
authors.initials: LM
authors.lastname: Tran
authors.forename: Andrzej J
authors.initials: AJ
authors.lastname: Zaleski