CXXV. On the destruction of superconductivity by large currents

Abstract

A theoretical study is made of the restoration of resistance in super-conducting wires by large currents. The experiments of Shubnikov and Alexeevsky and of Scott show a marked deviation from the theory of F. London. The present theory uses the same geometrical model of the structure as London, i.e. a string of superconducting conical domains along the axis of the wire. But it takes account of the effect on the resistance of the. scattering of electrons at successive normal-super-conducting interfaces, when their separation is comparable to the mean free path of the electrons in the normal phase. The scale of the structure is determined by minimizing the ‘Magnetic Gibbs’ Function’. It is shown that the interfacial surface energy may be neglected. The theory is in fair agreement with the rather scanty experimental data. The only parameter of the theory is the mean free path of electrons, and the value assigned is consistent with that obtained from other phenomena.