Superconducting properties of Rh$_{9}$In$_4$S$_4$ single crystals

Abstract

The synthesis and crystallographic, thermodynamic and transport properties of single crystalline Rh9In4S4 were studied. The resistivity, magnetization and specific heat measurements all clearly indicate bulk superconductivity with a critical temperature, Tc ∼ 2.25 K. The Sommerfeld coefficient γ and the Debye temperature(ΘD) were found to be 34 mJ mol −1 K −2 and 217 K respectively. The observed specific heat jump, ∆C/γTc = 1.66, is larger than the expected BCS weak coupling value of 1.43. Ginzburg-Landau (GL) ratio of the low temperature GL-penetration depth, λGL≈ 5750 Å, to the GL-coherence length, ξGL≈ 94 Å, is large: κ ∼ 60. Furthermore, we observed a peak effect in the resistivity measurement as a function of both temperature and magnetic field.