Intrinsic Josephson Arrays in HTSC Thin Films — Novel Approach with TlBaCaCuO — YBaCuO Multilayers

The intrinsic Josephson effect was sucessfully established with TIBaCaCuO thin films across a step in (100)LaAlO3 substrates (Step Stack junctions). I — V- characteristics showed all the single junctions in stack. Emitted microwave radiation was detected as broad, unsynchronized emission for temperatures close to Tc, but especially as sharp peaks resulting from phase locking at least of substacks for frequencies from 10 to 100 GHz. To improve the reproducibility and decrease parameter spread a in situ laser tuning was set up resulting in samples with Ic values up to 12 mA and a decrease in AIC of the individual junctions as well as of the McCumber parameter pc For further device applications a new concept and first experiments based on YBCO — TBCCO — multilayers are introduced