Size, order, and interface effects on PrBa/sub 2/Cu/sub 3/O/sub 7/ barriers

The artificially varied structural quality of interfaces significantly affects the transport properties of YBa/sub 2/Cu/sub 3/O/sub 7/-PrBa/sub 2/Cu/sub 3/O/sub 7/-YBa/sub 2/Cu/sub 3/O/sub 7/ junctions. The mechanism of conductivity changes from a semiconducting-like to a metal-like one with an improvement of the interface quality, the microstructure of the materials and the reduction of the barrier thickness. The proposed model including a carrier induced superconductivity and a bending of the electronic bands at the interfaces gives a satisfactory explanation of the experimental results.