The electrical behavior of superconducting thin-film microbridges self-heating and superconducting quantum processes

Measurements of the I-V curves of superconducting thin-film microbridges are reported and used to infer some new results regarding the electrical behavior of these devices. At temperatures well below Tc their behavior is found to be dominated by the effects of self-heating. At low voltages near Tc where heating is not important, it is found that the observed behavior is best understood in terms of a phase-slip mechanism and that the normal currents which flow during the phase-slip process extend over a range determined by the quasiparticle diffusion length. Even near Tc heating becomes important at high voltages and probably puts a limit on the maximum voltage (hence Josephson frequency) up to which useful Josephson-like behavior can be obtained.