Superconducting properties of an equiatomic hexagonal high-entropy alloy via muon spin relaxation and rotation measurement

Superconducting high-entropy alloys (HEAs) present a unique platform for studying the effect of disorder, composition, and crystal structure on superconducting pairing. In this study, we present a comprehensive bulk and microscopic investigation of the rarely observed equiatomic hexagonal HEA Nb-Mo-Ru-Re-Ir using magnetization, resistivity, heat capacity, and muon spin relaxation and rotation ($\textmu{}\mathrm{SR}$) measurements. Our findings confirm bulk type-II superconductivity with a transition temperature of 4.63(2) K and a high upper critical field. Heat capacity and transverse-field $\textmu{}\mathrm{SR}$ data reveal conventional $s$-wave superconductivity, while zero-field $\textmu{}\mathrm{SR}$ results suggest the preservation of time-reversal symmetry in the superconducting state. These findings provide valuable insights into the superconducting pairing mechanism in disordered multicomponent systems.