Sub-micron thin film intrinsic Josephson junctions

We have fabricated sub-micron intrinsic Josephson junctions in thin films of Tl-Ba-Ca-Cu-O using two differing techniques suited to different applications. By using lateral focussed ion-beam milling we have created arrays of intrinsic junctions in c-axis oriented films. Such arrays, with areas as low as 0.25 μm², display large hysteresis comparable to that observed in single-crystal intrinsic junctions. By using normal focussed ion-beam milling we have created arrays in mis-aligned films grown on vicinal substrates. In arrays of area less than 0.4 μm² we observe Josephson phase diffusion and a suppressed critical current, showing that charging effects may be significant in these junctions.