Superconducting properties in Rh17S15 under magnetic field and pressure

We have studied superconducting properties by measuring the electrical resistivity and magnetization for a single crystal of Rh17S15 with a superconducting transition temperature Tc=5.4 K. The upper critical field Hc2(0) and the lower critical field Hc1(0) were obtained as 20.5 and 0.0033 T, respectively. Correspondingly, the coherence length and the penetration depth were estimated to be 40 and 4900 Å, respectively, indicating that Rh17S15 is a typical type-II superconductor with strong correlations of conduction electrons with a 4d-electron character of Rh atoms. The present electron correlations are formed to be enhanced with increasing pressure.