Structural and Superconducting Proximity Effect of SnPb Bimetallic Nanoalloys

We report the superconducting properties between a conventional strong-coupled Pb and weak-coupled Sn superconductor. A series of Sn_rPb_1-r nanoalloys with various compositions r were synthesized, and their superconducting properties were measured using superconducting quantum interference devices (SQUIDs) magnetometer. Our results reveal a superconducting proximity effect (SPE) between immiscible Sn and Pb granules in the range of r = 0.2~0.9, as a weak superconducting coupling can be established with the coexistence of phonon hardening and increased Ginzburg-Landau coherence length. Furthermore, our results provide new insights into improving the study of the superconducting proximity effect introduced by Sn doping.