Properties of YBaCuO step-edge Josephson junction series arrays

YBa/sub 2/Cu/sub 3/O/sub 7/ (YBCO) structures composed of 10 and 100 step-edge Josephson junction series arrays incorporated into two-arm logarithmic spiral or bow-tie type were designed, fabricated by pulsed-laser deposition on structured LaAlO/sub 3/ substrates and measured in the temperature range 12 to 70 K at frequencies up to 150 GHz. At 18 K the I/sub c/R/sub N/ product of 10 junction arrays was up to 0.8 mV. Wide Shapiro steps at voltages corresponding to the multiple frequency of irradiation of 100 and 150 GHz were measured, as well as the emitted power and the linewidth at 12 GHz. In some arrays, 30 to 40% of the junctions were phase locked. This indicated that the spread of critical parameters of that fraction of the total junction population did not exceed 10%.<
>