Properties of Bi-2212/Bi-22Y2 step-stack Josephson junctions

We hare fabricated step-stack Josephson junctions based on high quality epi taxial BSCCO (2212 phase) thin films, deposited on Y-doped bismuth (Bi-22Y2 ) steps. Bi-2212 and Bi-22Y2 films were grown by a high oxygen pressure de- sputtering technique. The structural characteristics have been analyzed by x-ray, transmission electron microscopy (TEM), and Rutherford backscatterin g spectrometry (RBS). Bi-22Y2 steps between 100 and 300 nm high were patter ned by photolithography and non-aqueous chemical etching. Junctions were ch aracterized by current-voltage (I-V) measurements under magnetic fields and micromave irradiation. I-V curves have shown a clearly hysteretic weak-lin k Josephson behavior at different temperatures. The temperature dependence of the critical current in these step-stack junctions has also been analyze d.