Current transport in ramp-type junctions with engineered interface

The transport properties of "interface-engineered" edge-type YBa2Cu3O7 Jose phson junctions are investigated in detail. We have investigated the depend ence of the current-voltage characteristics on external magnetic field, tem perature, and microwave irradiation and compare them to the resistively shu nted junction model. The temperature dependence of the critical current and the normal resistance allows us to draw conclusions to the transport of qu asiparticles and Cooper pairs in the investigated "interface-engineered" ju nctions. We have studied the properties of junctions for which La doped YBa 2Cu3O7 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 wh ich consists of a series connection of a normal conducting layer and an ins ulator, containing superconducting microconstrictions. (C) 2001 American In stitute of Physics.