This Letter reports the results of a systematic study of the current-induced noise at the superconducting transition in thin, high-resistivity films of aluminum and tin. Analysis of the noise suggests that the onset of resistance is due to discrete phase slips of magnitude less than $2\pi$. The results are discussed in terms of the vortex unbinding models of the superconducting transition in two dimensions.

• Received 11 August 1980

DOI:https://doi.org/10.1103/PhysRevLett.45.1523