Localized resistive regions in superconducting thin films

A phenomenological model for resistive domains produced in semiconducting thin films on passage of a transport current through them is presented. The resistivity is pronouncedly nonequilibrium and is due to a magnetic flux through the specimen. The domains appear at sites of edge defects or inhomogeneities whose role reduces to lowering of the potential barrier to the entrance of the vortices. The kinetics of the flux in the specimen and the dissipation caused by it are considered. The heat-balance equation for a film with a domain is solved and the current-voltage characteristic (CVC) is calculated. Some quantitative features of the CVC are predicted, viz., absence of hysteresis at thermostat temperature T0 close to the superconductor critical temperature T/sub c/, the presence of a voltage discontinuity under given-current conditions, passage of the differential conductivity sigma(T0) of the initial resistive part of the CVC through a maximum, the presence of an excess current in the resistive part on the forward CVC after the temperature instability sets in, and others. Results are presented of an experimental verification of the model by measuring the CVC of thin indium films at thermostat temperatures zeta0 = 1-T0/T/sub c/ between 10-4 and 10-1. The experimental and theoretical results are compared qualitatively and quantitatively