Superconductivity in Cubic A15-type V–Nb–Mo–Ir–Pt High-Entropy Alloys

We report the crystal structure and superconducting properties of new V 5+2 x Nb 35− x Mo 35− x Ir 10 Pt 15 high-entropy alloys (HEAs) for x in the range of 0 ≤ x ≤ 10. These HEAs are found to crystallize in a cubic A15-type structure and have a weakly coupled, fully gapped superconducting state. A maximum T c of 5.18 K and zero-temperature upper critical field Bc2 (0) of 6.4 T are observed at x = 0, and both quantities decrease monotonically with the increase of V content x . In addition, T c shows an increase with increasing valence electron concentration from 6.4 to 6.5, which is compared with other A15-type HEA and binary superconductors.