Superconductivity of niobium phosphorous sulphide, NbPS, prepared at high pressure

Electrical resistivity and de susceptibility of NbPS prepared at high press ure have been studied at low temperatures. The compound showed a supercondu cting transition at around 12 K. The resistance of NbPS was measured as a f unction of an applied magnetic field at constant temperature. The upper cri tical held obtained from this data was 17 tesla (T) at 0 K. This is the hig hest value reported in phosphide superconductors. The coherence length of t he compound was found to be 44.0 Angstrom. Adiabatic specific-heat measurem ents on NbPS were performed in the temperature range 2 and 20 K. The heat c apacity fitted to the expression C = gamma T +beta T-3, by a least squares analysis, yielded the values gamma = 6.5 ml mol(-1) K-2 and beta = 0.6 mJ m ol(-1) K-4. Th, Debye temperature (OD) of NbPS was found to be 330 K. The d ensity of states at the Femir level was calculated to be 0.51 states eV(-1) /atom.