ThicI~nessdependence of the superconducting transition temperature of YBCO
نویسندگان
چکیده
We have performed detailed structuraland superconducting studies of YBCO single layers, YBCO/PrBCO/YBCO tn-layers, and YBCØ/PrBCO superlattices.The results for single layers indicate that a nominally one unit cell thick YBCO film sandwiched between ~rBCO layers is not superconducting. However, a superlattice with nominally one unit cell thick YBCO layers has a measurabte superconducting temperature onset (T~).These apparently contradictory results arereconciled by experiments on YBCO/PtBCO/YBCO tn-layers which, due to coupling across the PrBCO insulating layer, exhibit superconductivity for PrECO thicknesses below 200 A. Structural studies show that the length scale of the superconductive coupling is much larger than the length scaleof the step disorder and interdiffusion present in the film.
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