Superconducting Properties and μSR Study of the Noncentrosymmetric Superconductor Nb_0.5Os_0.5.

The properties of the noncentrosymmetric superconductor (alpha-Mn structure) Nb0.5Os0.5 have been investigated using resistivity, magnetization, specific heat, and muon spin relaxation and rotation (mu SR) measurements. These measurements suggest that Nb0.5Os0.5 is a weakly coupled (lambda(e-ph) similar to 0.53) type-II superconductor (kappa(GL) approximate to 61), having a bulk superconducting transition temperature T-c = 3.07 K. The specific heat data fits well with the single-gap BCS model indicating nodeless s-wave superconductivity in Nb0.5Os0.5. The mu SR measurements also confirm s-wave superconductivity with the preserved time-reversal symmetry.