Coexistence of superconductivity and superparamagnetism in Pb–Co electrodeposited nanowires

Abstract

Pb–Co nanowires were electrodeposited in 100 nm nominal pore diameter polycarbonate membranes. Above the TC of Pb we modelled the behaviour of the wires with a Langevin function, obtaining a Co volume of (1.06 ± 0.01) × 10−7 cm3 divided into clusters of ≈10 atoms in size. The magnetic response of the wires in the 3–10 K interval, which comprises TC, was modelled by adding spherical superconducting Pb grains to the Co clusters; the Pb grains were found to be (87 ± 6) nm in diameter. The Co clusters were not interacting and were not magnetically screened by the superconducting Pb.