Potential Fluctuations in the Transition Region to Superconductivity

Gorter recently proposed a dynamical model to describe the state of a current-carrying wire, in the transition region to superconductivity. This model predicts in the transition region to superconductivity an alternating component of the potential difference across a wire carrying a strong direct current. The magnitude of this fluctuation should be of the order of a few percent of the average potential. Using a shielded transformer in the liquid helium and a battery-operated preamplifier, detection of this alternating component has been attempted. The noise output was somewhat larger when the sample was in the intermediate state than when it was in the superconducting state. However, instead of being a few percent of the average potential (as in the Gorter model), this additional alternating potential was only about one hundredth of one percent. It may be due partially to a slightly drifting bath temperature, since vibrations made it necessary to switch the pump off about 10 sec before the readings were taken.

Перевод пока недоступен