Current transport in ramp-type junctions with engineered interface

The transport properties of "interface-engineered" edge-type YBa₂Cu₃O₇ Josephson junctions are investigated in detail. We have investigated the dependence of the current-voltage characteristics on external magnetic field, temperature, and microwave irradiation and compare them to the resistively shunted junction model. The temperature dependence of the critical current and the normal resistance allows us to draw conclusions to the transport of quasiparticles and Cooper pairs in the investigated "interface-engineered" junctions. We have studied the properties of junctions for which La doped YBa₂Cu₃O₇ is used for the superconducting electrodes. We will propose a model for the undoped and the La doped case which takes into account a barrier which consists of a series connection of a normal conducting layer and an insulator, containing superconducting microconstrictions.