Current-induced destruction of type I superconductivity: The role of the one- and two-dimensional mixed state

New experimental and theoretical results on the current-induced phase transition in cylindrical wires (tin) are presented: The London model for the intermediate state of current-carrying superconductors has been modified, taking into account magnetoresistance, and has been extended to hollow cylinders. Evidence for the one- and two-dimensional mixed state first proposed by Landau has been obtained from the study of the quasistatic voltage-current curves of solid and hollow cylindrical specimens, respectively. The kinetic phenomena during the current-induced destruction of superconductivity in solid cylindrical wires have previously been studied by Posada and Rinderer, but only measurements on hollow wires of high purity presented in this paper confirm the isothermal electromagnetic theory of Rothen and Bestgen for a current-induced phase transition. For currents close to Silsbee's critical current, in pure specimens as well as for impure specimens, for any current above the critical, the dynamic destruction of superconductivity in wires is no longer isothermal. For these cases the nonisothermal theory of Posada and Rinderer has been extended to the case of hollow cylinders and successfully compared with experiments.This work was supported financially by the Fonds National Suisse pour la Recherche Scientifique.