Phase slips in submicrometer YBaCu3O7-δ bridges -: art. no. 174506

We have measured the resistance vs temperature, R(T), and current vs voltage, I(V), for a series of submicrometer YBa2Cu3O7-delta tracks. We find that superconductivity is suppressed when the room temperature resistance is greater than the superconducting resistance quantum, R-q=h/4e(2). In addition, we observe regular steps in the I(V) characteristics of some bridges, which we associate with phase slip centers. For one bridge, with resistance just below the resistance quantum, R-q, we find a gradual entry into the superconducting state which is well fit by theoretical predictions for thermally activated phase slips in a superconducting wire.