A HIGH-TC JOSEPHSON-JUNCTION ON A NARROW TUNGSTEN LINE FORMED BY FOCUSED ION BEAN CHEMICAL-VAPOR-DEPOSITION

We have fabricated two types of high-Tc Josephson junctions using a fo cused ion beam technique. High-Tc junctions fabricated using a narrow- focused Ga-ion beam to damage a substrate, resulting in a geometrical defect prior to High-Tc layer deposition, show flux flow-like characte risics for the SrTiO3 substrate. The current-voltage characteristics o f the junctions which are fabricated on a narrow tungsten (W) metal la yer deposited on both MgO and SrTiO3 substrates using a focused ion be am chemical vapor deposition technique are qualitatively consistent wi th a resistively shunted junction model and show Shapiro steps under m icrowave irradiation.