Low-frequency impedance of the direct current induced intermediate state in superconductors: I. The in-phase component

Abstract

We have measured the in-phase component of the low-frequency ac impedance of the dc current-induced intermediate state in indium-lead alloywires. The specimens were mounted in a specific configuration that allowed a proper calculation of their dynamic resistances following the theory developed by Gauthier and Rochon, which is based on London's theory of the intermediate state. The theoretical values are considerably larger than our measurements, particularly near the critical current. We have modified the Gauthier-Rochon theory, to a first approximation, to take account of the Baird-Mukherjee model of the intermediate state and we find reasonably good agreement between the modified theoretical values and our observations.