Influence of a bulk superconducting environment on the superconductivity of one-dimensional zinc nanowires

In an earlier paper [Tian et al., Phys. Rev. Lett. 95, 076802 (2005)], we reported an antiproximity effect (APE) in a system consisting of 400.3em0exnm diameter Zn nanowires (ZNWs) sandwiched between bulk Sn and In electrodes. When the electrodes are in the superconducting state, the superconductivity of the ZNWs is suppressed. When the electrodes are driven normal by a magnetic field, the superconductivity of the ZNWs recovers. In this paper we report systematic transport studies of this phenomenon with ZNWs sandwiched between Pb electrodes. The APE found in this system is subtle, showing up primarily in significantly reducing the critical current of the ZNWs when the Pb electrodes are in a superconducting state. The critical current is independent of the magnetic field until it is increased to a characteristic value Hᵈ near 0.60.3em0exkOe when the critical current shows a rapid enhancement and reaches a maximum value at the critical field of Pb electrodes at 0.940.3em0exkOe.