PLANAR THIN-FILM YBA2CU3O7-DELTA JOSEPHSON-JUNCTIONS VIA NANOLITHOGRAPHY AND ION DAMAGE

We have developed a process to fabricate planar high-T-c Josephson jun ctions using nanolithography and a 200 keV ion implanter. Conduction o ccurs in the ab plane and is interface free. We can systematically tun e devices to operate at temperatures between 1 K and the T-c of the un damaged superconducting material by varying the length of the weak lin k and by changing the amount of ion damage. All of the devices showed clear de and ac Josephson effects. Measurement of R(T) and I-c(T) of t he weak Links revealed trends which were consistent with a proximity e ffect. (C) 1998 American Institute of Physics.