The electrical conductivity of bundles of superconducting nanowires produced by laser ablation of metals in superfluid helium

The temperature dependencies of the electrical resistance are reported for bundles of permalloy, indium, tin, and lead nanowires having a similar diameter of about 8 nm which were grown by catalytic coagulation of laser ablation products in quantized vortices of superfluid helium. In all metals, the constant residual resistance found at low temperatures changes to a superlinear growth at higher temperatures. For all superconducting nanowires, the transition to superconductivity is broadened with a width of δT = 0.6 K. The size shift of the transition center ΔT is largest for lead, ΔT = -2 K, whereas for indium and tin ΔT is 0.2 K and <0.1 K, respectively.