Binary-divided 1 V arrays were fabricated for programmable Josephson voltage standards in close cooperation between INRIM and PTB. The arrays, consisting of 8192 overdamped Nb/Al-AlO(x)Nb SNIS Josephson junctions, were successfully operated at microwave frequencies around 70 GHz. While the characteristic voltage of the junctions ranged from 0.25 to 0.6 mV, the current margins were larger than 1 mA for the Shapiro step n = 1. In addition, flat Shapiro steps of higher order (n = 3 and 4) were generated at increased microwave power levels due to the large characteristic voltage, demonstrating the small parameter spread of the SNIS junctions. Operation at temperatures up to 6-7 K has also been verified, measuring quantized voltages up to 1.25 V on the n = 1 step.
1 V programmable voltage standards based on SNIS Josephson junction series arrays / Lacquaniti, Vincenzo; DE LEO, Maria; Fretto, MATTEO ANDREA; Sosso, Andrea; Mueller, F; Kohlmann, J.. - In: SUPERCONDUCTOR SCIENCE & TECHNOLOGY. - ISSN 0953-2048. - 24:4(2011), p. 045004.045004. [10.1088/0953-2048/24/4/045004]
1 V programmable voltage standards based on SNIS Josephson junction series arrays
LACQUANITI, VINCENZO;DE LEO, MARIA;FRETTO, MATTEO ANDREA;SOSSO, ANDREA;
2011
Abstract
Binary-divided 1 V arrays were fabricated for programmable Josephson voltage standards in close cooperation between INRIM and PTB. The arrays, consisting of 8192 overdamped Nb/Al-AlO(x)Nb SNIS Josephson junctions, were successfully operated at microwave frequencies around 70 GHz. While the characteristic voltage of the junctions ranged from 0.25 to 0.6 mV, the current margins were larger than 1 mA for the Shapiro step n = 1. In addition, flat Shapiro steps of higher order (n = 3 and 4) were generated at increased microwave power levels due to the large characteristic voltage, demonstrating the small parameter spread of the SNIS junctions. Operation at temperatures up to 6-7 K has also been verified, measuring quantized voltages up to 1.25 V on the n = 1 step.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
