Superconductivity of Y5Rh6Sn18; Coexistence of the high temperature thermal lattice relaxation process and superconductivity

Abstract

The heat capacity, magnetic, and electrical transport properties of skutterudite-related Y5Rh6Sn18 compound indicate intriguing coexistence of the high temperature thermal lattice relaxation process at temperatures higher than 350 K and superconductivity below the superconducting transition temperature Tc=3.08 K. Y5Rh6Sn18, having a cage-like structure crystallises in tetragonal structure with the space group I41/acd. The gap structure of this compound is found not to be characteristic of conventional BCS type superconductors. Anomalous behaviour observed in the electronic specific heat C(T)/T and the upper critical field Hc2(T) data may suggest the presence of two superconducting gaps in this compound. The ab initio band structure calculations showed a significant contribution of s and p Sn states as well as Rh and Y d-electron states to the total density of states near the Fermi level, which supports the multi-band superconductivity of this compound. Several electronic quantities and parameters characterising the superconducting and normal state of Y5Rh6Sn18 are calculated within the Ginzburg-Landau-Abrikosov-Gorkov theory. The data reveals dirty limit superconductivity in Y5Rh6Sn18 superconductor of type-II.