Superconducting properties in Rh sub(17)S sub(15) under magnetic field and pressure

We have studied superconducting properties by measuring the electrical resistivity and magnetization for a single crystal of Rh sub(17)S sub(15) with a superconducting transition temperature T sub(c)=5.4 K. The upper critical field H sub(c2)(0) and the lower critical field H sub(c1)(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 Aa, respectively, indicating that Rh sub(17)S sub(15) 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.