RESISTANCE ANOMALIES IN SUPERCONDUCTING MESOSCOPIC AL STRUCTURES

We present a detailed study of the recently reported resistance peaks close to the superconducting transition of quasi-one-dimensional mesos copic Al structures. It is found that the anomalies can be induced by radio-frequency irradiation or by applying sufficiently high dc curren ts. The nonmonotonic resistance curves are correlated with excess volt ages in the voltage-current characteristics close to the critical curr ent and depend strongly on the temperature and the magnetic field. The experimental results can be qualitatively understood in terms of char ge imbalance around phase-slip centers which nucleate at particular sp ots in the sample with a locally reduced transition temperature. [S016 3-1829(98)05717-8].