Title :
Stacked niobium Josephson junction arrays under x-band irradiation
Author :
Klushin, A.M. ; Schornstein, S. ; Kohlstedt, H. ; Wende, G. ; Thrum, F. ; Meyer, H.-G.
Author_Institution :
Inst. fur Schicht- und Ionentechnik, Forschungszentrum Julich GmbH, Germany
fDate :
6/1/1997 12:00:00 AM
Abstract :
Stacked Josephson junction arrays located at the rf current antinodes of a superconducting microstripline resonator were investigated. The circuits were designed to obtain highly accurate voltages at cm-waveband microwave driving and low rf-power level. Nb-Al/AlO/sub x/-Nb Josephson junctions with tunneling area of 60 /spl mu/m/spl times/300 /spl mu/m and critical current density up to 7 A/cm/sup 2/ were used. We compared the average voltages of the rf induced maximal current steps in arrays with up to three junctions per stack. Quantized current steps up to 300 mV were observed under microwave irradiation at frequency of 19.20 GHz in circuits with 384 three-junction stacks. The dynamics of stacked tunnel junctions in the presence of rf-currents will be discussed with respect to application as voltage standards.
Keywords :
Josephson effect; microstrip circuits; microstrip resonators; niobium; superconducting microwave devices; superconducting resonators; 19.20 GHz; Nb-Al-AlO-Nb; Nb-Al/AlO/sub x/-Nb stacked Josephson tunnel junction array; RF current antinode; X-band microwave irradiation; critical current density; quantized current steps; superconducting microstripline resonator circuit; voltage standard; Critical current density; Frequency; Josephson junctions; Microstrip antenna arrays; Microstrip resonators; Microwave circuits; Niobium; Superconducting microwave devices; Tunneling; Voltage;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
