Superconducting to Normal Phase Transition in Tantalum

Abstract

Measurements were made of the rate at which the superconducting phase collapses radially in a hollow cylindrical tantalum specimen following the sudden application of a longitudinal magnetic field greater than the critical field. The measured transition rates confirm the hypothesis that the propagation is controlled by electromagnetic damping associated with eddy currents generated in the normal phase. The results, moreover, may be interpreted on the basis of a theoretical treatment of the problem first published by Pippard, provided that suitable modifications are incorporated to include the thermal effects which accompany the transition.