Superconducting properties and μSR study of the noncentrosymmetric superconductor Nb_0.5Os_0.5

The properties of the noncentrosymmetric superconductor (α-$Mn$ structure) Nb_0.5Os_0.5 have been investigated using resistivity, magnetization, specific heat, and muon spin relaxation and rotation (μSR) measurements. These measurements suggest that Nb_0.5Os_0.5 is a weakly coupled (${\lambda }_{e-ph}\sim 0.53$) type-II superconductor (${\kappa }_{GL}\approx 61$), 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 Nb_0.5Os_0.5. The μSR measurements also confirm $s$-wave superconductivity with the preserved time-reversal symmetry. (paper)