Supercurrents and dynamic resistivities in periodic arrays of superconducting-normal contacts

Abstract

Periodic $\mathrm{SNSN}\cdots$ systems have been obtained by directional solidification of Pb-Sn lamellar eutectic. The temperature and field dependence of critical currents have been measured. The former is well described by a model of quantized quasiparticle levels in the normal regions. Supercurrents show interference patterns in the presence of a magnetic field which become less marked as the superconducting critical temperature of $\mathrm{Sn}$ is approached. An unexpected change of a few orders of magnitude in differential resistivity above the critical current is observed at a certain temperature in exceptionally clean samples. An attempt to explain this phenomenon is given in terms of the aforementioned quantized-level model.