Electrical field dependence of the quasi-particle transport in YBa_2Cu_3O_7 Josephson junctions in ramp-edge geometry

摘要

The electrical transport properties of ramp-edge Josephson junctions with PrBa_2Cu_3O_7 barriers are investigated with respect to the variation of the barrier thickness. In a Josephson junction with a barrier thickness of 100 nm variable-range hopping dominates the transport as analyzed from the electric field dependence of the quasi-particle conductivity. For thinner barriers resonant tunneling through only a few localized states is dominant. We investigate the dependence of the critical current through these barriers on the corresponding quasi-particle transport properties. We find strong peaks in the differential resistance dU/dI in dependence on the bias current.