Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

IEEE Transactions on Applied Superconductivity

Constant-voltage steps in arrays of Nb-PdAu-Nb Josephson junctions

Samuel P. Benz, Charles J. Burroughs

Published Jun 1, 1997• 24 citations
Publisher

Abstract

Design and fabrication of Nb-PdAu-Nb trilayer Josephson junctions are described. The microwave response of an array of 1000 of these junctions was measured, and constant-voltage step heights mere characterized as a function of the microwave amplitude and frequency. Experimental results fit well to point-junction simulations at the 3 GHz design frequency of the microwave distribution network. The observed step height of 3.8 mA shows that the array and microwave distribution are sufficiently uniform for application in programmable Josephson voltage standards.

DOI
10.1109/77.621732

Related papers

Superconductor-normal-superconductor junctions for programmable voltage standards

S. P. Benz

Series arrays of Nb–PdAu–Nb Josephson junctions were fabricated with characteristics ideally suited for application in programmable voltage standards and D/A converters with fundamental accuracy. Large arrays of junctions with applied microwave power showed constant voltage steps with current amplitudes as large as 7 mA. A novel coplanar waveguide design enabled uniform microwave power coupling to a five-segment array of 8192 junctions, so each segment had constant voltage steps over the same bias range. The 8192-junction device generated 1.1 mA steps at 186 mV with 11 GHz power and a maximum constant voltage step of 260 mV at 15.34 GHz.

Applied Physics Letters•Oct 30, 1995•133 citations

10 V SINIS Josephson junction series arrays for programmable voltage standards

J. Kohlmann, H. Schulze, Ralf Behr +2 more

A programmable dc voltage standard for output voltages of up to 10 V has been realized. The series arrays, consisting of about 69120 overdamped superconductor/insulator/normal metal/insulator/superconductor (SINIS) Josephson junctions, have been fabricated using the reliable Nb-Al/Al/sub 2/O/sub 3/ technology. The arrays can be operated in conventional Josephson voltage standards at microwave frequencies from 70 GHz to 75 GHz. Steps of constant voltage are observed at very low microwave power levels, since the major part of the microwave power is generated by the junctions themselves. The operation of the arrays and the formation of Shapiro steps are discussed.

IEEE Transactions on Instrumentation and Measurement•Apr 1, 2001•20 citations

1 V programmable voltage standards based on SNIS Josephson junction series arrays

V. Lacquaniti, Natascia De Leo, Matteo Fretto +3 more

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.

Superconductor Science and Technology•Jan 27, 2011•37 citations

Development and investigation of Nb-Al-oxide-Nb Josephson junction arrays [voltage standard application]

A.F. Bochanov, V.D. Gelikonova, Alexander M. Klushin +2 more

An array of 3072 Josephson junctions Nb-AlO/sub x/-Nb is developed at IEM "KVARZ". Some preliminary results of an investigation of I-V curves under microwave irradiation in the 70 GHz frequency band are given. Zero current quantized voltage steps are displayed up to 450 mV with an amplitude >100 /spl mu/A. An improvement of the fabrication process, which is in progress, will enable to increase quantized voltage steps region up to 1 V.>

Conference on Precision Electromagnetic Measurements•Dec 17, 2002•0 citations

Large constant voltage generated with a single array including 65 536 Nb/TiN/Nb Josephson junctions

Hirotake Yamamori, Chiharu Urano, Michitaka Maruyama +2 more

A 2 V Shapiro step with a current height of about 0.3 mA was successfully generated at 4.2 K with a single array including 65 536 Nb/TiN/Nb Josephson junctions under microwave irradiation at 16 GHz. The critical current density was 89 kA cm − 2 , and the junction size was 3 µm. The n = 1 step height decreased exponentially as the number of junctions N increased when the number of junctions was less than 30 000, a result that agreed well with the dissipated junction model. On the other hand, the step height was nearly constant when the number of junctions was more than about 30 000, a figure much larger than that theoretically calculated from the model. Using an array including such a large number of Josephson junctions represents a promising way for ac waveform synthesis to increase output voltage to about 1 V rms .

Superconductor Science and Technology•Jun 16, 2010•5 citations

Development of 0.5-V Josephson junction array devices for quantum voltage standards*

Lanruo Wang, Jinjin Li, Wenhui Cao +2 more

The design, fabrication, and the characterization of a 0.5-V Josephson junction array device are presented for the quantum voltage standards in the National Institute of Metrology (NIM) of China. The device consists of four junction arrays, each of which has 1200 3-stacked Nb/Nb x Si1−x /Nb junctions and an on-chip superconducting microwave circuit which is mainly a power divider enabling each Josephson array being loaded with an equal amount of microwave power. A direct current (dc) quantum voltage of about 0.5 V with a ∼1-mA current margin of the 1st quantum voltage step is obtained. To further prove the quality of NIM device, a comparison between the NIM device with the National Institute of Standards and Technology (NIST) programmable Josephson voltage standard (PJVS) system device is conducted. The difference of the reproduced 0.5-V quantum voltage between the two devices is about 0.55 nV, which indicates good agreement between the two devices. With the homemade device, we have realized a precise and applicable 0.5-V applicable-level quantum voltage.

Chinese Physics B•Jun 1, 2019•5 citations
Design and fabrication of Nb-PdAu-Nb trilayer Josephson junctions are described. The microwave response of an array of 1000 of these junctions was measured, and constant-voltage step heights mere characterized as a function of the microwave amplitude and frequency. Experimental results fit well to point-junction simulations at the 3 GHz design frequency of the microwave distribution network. The observed step height of 3.8 mA shows that the array and microwave distribution are sufficiently uniform for application in programmable Josephson voltage standards.
Series arrays of Nb–PdAu–Nb Josephson junctions were fabricated with characteristics ideally suited for application in programmable voltage standards and D/A converters with fundamental accuracy. Large arrays of junctions with applied microwave power showed constant voltage steps with current amplitudes as large as 7 mA. A novel coplanar waveguide design enabled uniform microwave power coupling to a five-segment array of 8192 junctions, so each segment had constant voltage steps over the same bias range. The 8192-junction device generated 1.1 mA steps at 186 mV with 11 GHz power and a maximum constant voltage step of 260 mV at 15.34 GHz.
A programmable dc voltage standard for output voltages of up to 10 V has been realized. The series arrays, consisting of about 69120 overdamped superconductor/insulator/normal metal/insulator/superconductor (SINIS) Josephson junctions, have been fabricated using the reliable Nb-Al/Al/sub 2/O/sub 3/ technology. The arrays can be operated in conventional Josephson voltage standards at microwave frequencies from 70 GHz to 75 GHz. Steps of constant voltage are observed at very low microwave power levels, since the major part of the microwave power is generated by the junctions themselves. The operation of the arrays and the formation of Shapiro steps are discussed.
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.
A 2 V Shapiro step with a current height of about 0.3 mA was successfully generated at 4.2 K with a single array including 65 536 Nb/TiN/Nb Josephson junctions under microwave irradiation at 16 GHz. The critical current density was 89 kA cm − 2 , and the junction size was 3 µm. The n = 1 step height decreased exponentially as the number of junctions N increased when the number of junctions was less than 30 000, a result that agreed well with the dissipated junction model. On the other hand, the step height was nearly constant when the number of junctions was more than about 30 000, a figure much larger than that theoretically calculated from the model. Using an array including such a large number of Josephson junctions represents a promising way for ac waveform synthesis to increase output voltage to about 1 V rms .
The design, fabrication, and the characterization of a 0.5-V Josephson junction array device are presented for the quantum voltage standards in the National Institute of Metrology (NIM) of China. The device consists of four junction arrays, each of which has 1200 3-stacked Nb/Nb x Si1−x /Nb junctions and an on-chip superconducting microwave circuit which is mainly a power divider enabling each Josephson array being loaded with an equal amount of microwave power. A direct current (dc) quantum voltage of about 0.5 V with a ∼1-mA current margin of the 1st quantum voltage step is obtained. To further prove the quality of NIM device, a comparison between the NIM device with the National Institute of Standards and Technology (NIST) programmable Josephson voltage standard (PJVS) system device is conducted. The difference of the reproduced 0.5-V quantum voltage between the two devices is about 0.55 nV, which indicates good agreement between the two devices. With the homemade device, we have realized a precise and applicable 0.5-V applicable-level quantum voltage.