Fabrication and properties of YBCO tunnel junctions by ion beam sputtering

Au/SrTiO/sub 3//YBCO tunnel junctions were fabricated by ion beam sputtering. The electrodes of YBCO and SrTiO/sub 3/ barrier layer were deposited on MgO [100] substrate at 700/spl deg/C and 550/spl deg/C respectively. The electrodes of YBCO had a T/sub c/ of 70/spl sim/80 K. SrTiO/sub 3//YBCO bilayers have been examined by X-ray diffraction and the results show that both the YBCO and barrier layer were well oriented. The current-voltage (I-V) and dV/dI-V characteristics of the junctions were measured. In a pin hole free junction, the resistance dip, corresponding to the density of states, was obtained at voltage of 22 mV.<
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