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

Japanese Journal of Applied Physics

Constant-Voltage Steps in the V-I Curve of a J-J Loop

Sumitaka Takeuchi, Hidemi Narita, Tadayuki Kobayashi, Katsuyoshi Hamasaki, Shokichiro Yoshikawa, Tsutomu Yamashita

Published Dec 1, 1985• 2 citations
Publisher

Abstract

Both resonant and microwave-induced steps in the V-I characteristics of four-Josephson-junction loop with a small junction-parameter spread have been investigated. An rf current was superimposed onto a dc current and the radio frequency was tuned to the resonance frequency of the loop. In the high-Q region, the rf-power dependence of the step amplitude was similar to that of a single junction. However, we obtained V-I characteristics which indicated that the behavior of the junction in the loop was coherent in the low-Q region.

DOI
10.1143/jjap.24.1627

Related papers

RF-Induced Steps in the V-I characteristics of a Superconducting Closed Loop Formed form 2N-Josephson Junctions

Kenji Takanaka, Tadayuki Kobayashi, Tsutomu Yamashita

This paper reports a theoretical study of a superconducting closed loop consisting of a parallel connection of two linear series arrays of N-Jesephson junctions, exposed to a microwave field of frequency F. Constant-voltage steps in the current-voltage characteristics are found to appear at V dc=2m N F Φ_0, where m is an integer and Φ_0 is the flux quantum, if the loop inductance is small.

Japanese Journal of Applied Physics•Sep 1, 1984•2 citations

Calculation of the Shapiro step amplitudes in two-dimensional Josephson tunnel junction

U. Klein, S. Schroder, Johann Heyen Hinken

We have investigated theoretically the amplitudes of RF- induced constant voltage steps in two-dimensional Josephson tunnel junctions, using both a first-order approximation and a numerical it- eration procedure to calculate the current density distribution in the junction. We use a planar resonator model to analyze the electromag- netic field in the microwave-driven junction. Integrating the local Jo- sephson current density over the junction area yields the total dc current on a chosen Shapiro step. Numerical calculations of the Sha- piro step amplitudes in two-dimensional resonant junctions show a qualitatively different behavior from that in one-dimensional resonant junctions. Depending on the dominant resonant mode, the microwave power dependence of the step amplitude gives a smooth curve without zeros. This behavior is advantageous for biasing the Josephson junc- tion in its maximum step amplitude. The main difference between the results of the first-order approximation and the full theory is that- using the iteration procedure-the Shapiro steps in resonant junctions become asymmetric with respect to the quasi-particle curve. This is due to consideration of the losses and the internal Josephson currents in the numerical iteration procedure of the full theory.

IEEE Transactions on Instrumentation and Measurement•Apr 1, 1991•4 citations

I-Vcharacteristics of microwave-driven Josephson junctions in the low-frequency and high-damping regime

C. Vanneste, C. C., Karen H. Brown +10 more

Experimental I-V curves of microwave-driven Josephson tunnel junctions with resistive shunts are reported. The results are in very good agreement with numerical calculations using the resistively shunted junction model. In the low-frequency regime there are three distinct regions in the I-V curves and two different types of Shapiro steps. It is demonstrated that the overall shape of the I-V curves can be explained by using an adiabatic interpretation of the junction response. The two different types of Shapiro steps are related to a compensation effect between dc and rf bias currents.

Physical review. B, Condensed matter•Apr 1, 1985•22 citations

Influence of microwave phase noise on Josephson voltage steps

Gian Paolo Bava, Domenico Andreone, E. Bava +1 more

The influence of microwave phase noise on rf-induced constant voltage steps generated by the ac Josephson effect is studied. Different circuit models for the junction excitation are considered: dc and rf voltage generators, dc and rf current generators, dc current and rf voltage generators. The analysis has been carried out assuming a power and band limited phase noise modulation in the first two cases, while in the last one a white frequency modulation spectrum is required for a treatment based on the Fokker-Planck equation. Some experimental results are reported, in order to display the basic phenomenological behavior.

Journal of Applied Physics•Sep 1, 1982•4 citations

Microwave-induced current steps in intrinsic Josephson junctions patterned on Bi2Sr2CaCu2O8 single crystal

H.B. Wang, Yuta Aruga, Takashi Tachiki +5 more

With a 10 μm×10 μm mesa patterned on Bi2Sr2CaCu2O8 single crystals, we measure the current–voltage (I–V) curves of a stack of intrinsic Josephson junctions. Current steps are observed at an equal voltage spacing of 4 mV when the sample is subjected to microwave radiation at around 7 GHz. With increase of the microwave power, more steps occur while the spacing between neighboring steps does not seem to change. The magnitude of each step depends on the microwave power in an oscillating way. Tuning the microwave frequency causes such steps to occur over separate frequency ranges, and each range is quite narrow. A temperature rise from 4.2 to 14.3 K completely quenches the step structures. Possible explanations for the step structures, based on resonances excited by microwave or geometric resonances in the junction cavity, are discussed.

Applied Physics Letters•Jun 14, 1999•19 citations

RF-induced steps in mutually coupled, two-dimensional distributed Josephson tunnel junctions

U. Klein, P. Dammschneider, Johann Heyen Hinken

The amplitudes of the current steps in the I-V characteristics of mutually coupled two-dimensional distributed Josephson tunnel junctions driven by microwaves are investigated. For this purpose a numerical computation algorithm that is based on a planar resonator model for the individual Josephson tunnel junctions is used to calculate the DC current density distribution. In addition to the fundamental microwave frequency, harmonic contents of the tunneling current are also considered. The lateral dimensions of the individual junctions are small compared to the microwave wavelength and the Josephson penetration depth, giving an almost constant current density distribution. Therefore, the coupled junctions can give much greater step amplitudes than a single junction with an equal tunneling area, because of their nonuniform current density distribution. The calculation show a strong dependence of the Shapiro step amplitudes with respect to the coupling of the tunnel junctions. These studies imply that the choice of proper coupling conditions is important to achieve maximum step amplitudes. These results are helpful in designing tunnel junctions with optimized step amplitudes.

IEEE Transactions on Magnetics•Mar 1, 1991•1 citation
Both resonant and microwave-induced steps in the V-I characteristics of four-Josephson-junction loop with a small junction-parameter spread have been investigated. An rf current was superimposed onto a dc current and the radio frequency was tuned to the resonance frequency of the loop. In the high-Q region, the rf-power dependence of the step amplitude was similar to that of a single junction. However, we obtained V-I characteristics which indicated that the behavior of the junction in the loop was coherent in the low-Q region.
We have investigated theoretically the amplitudes of RF- induced constant voltage steps in two-dimensional Josephson tunnel junctions, using both a first-order approximation and a numerical it- eration procedure to calculate the current density distribution in the junction. We use a planar resonator model to analyze the electromag- netic field in the microwave-driven junction. Integrating the local Jo- sephson current density over the junction area yields the total dc current on a chosen Shapiro step. Numerical calculations of the Sha- piro step amplitudes in two-dimensional resonant junctions show a qualitatively different behavior from that in one-dimensional resonant junctions. Depending on the dominant resonant mode, the microwave power dependence of the step amplitude gives a smooth curve without zeros. This behavior is advantageous for biasing the Josephson junc- tion in its maximum step amplitude. The main difference between the results of the first-order approximation and the full theory is that- using the iteration procedure-the Shapiro steps in resonant junctions become asymmetric with respect to the quasi-particle curve. This is due to consideration of the losses and the internal Josephson currents in the numerical iteration procedure of the full theory.
Experimental I-V curves of microwave-driven Josephson tunnel junctions with resistive shunts are reported. The results are in very good agreement with numerical calculations using the resistively shunted junction model. In the low-frequency regime there are three distinct regions in the I-V curves and two different types of Shapiro steps. It is demonstrated that the overall shape of the I-V curves can be explained by using an adiabatic interpretation of the junction response. The two different types of Shapiro steps are related to a compensation effect between dc and rf bias currents.
The influence of microwave phase noise on rf-induced constant voltage steps generated by the ac Josephson effect is studied. Different circuit models for the junction excitation are considered: dc and rf voltage generators, dc and rf current generators, dc current and rf voltage generators. The analysis has been carried out assuming a power and band limited phase noise modulation in the first two cases, while in the last one a white frequency modulation spectrum is required for a treatment based on the Fokker-Planck equation. Some experimental results are reported, in order to display the basic phenomenological behavior.
With a 10 μm×10 μm mesa patterned on Bi2Sr2CaCu2O8 single crystals, we measure the current–voltage (I–V) curves of a stack of intrinsic Josephson junctions. Current steps are observed at an equal voltage spacing of 4 mV when the sample is subjected to microwave radiation at around 7 GHz. With increase of the microwave power, more steps occur while the spacing between neighboring steps does not seem to change. The magnitude of each step depends on the microwave power in an oscillating way. Tuning the microwave frequency causes such steps to occur over separate frequency ranges, and each range is quite narrow. A temperature rise from 4.2 to 14.3 K completely quenches the step structures. Possible explanations for the step structures, based on resonances excited by microwave or geometric resonances in the junction cavity, are discussed.
The amplitudes of the current steps in the I-V characteristics of mutually coupled two-dimensional distributed Josephson tunnel junctions driven by microwaves are investigated. For this purpose a numerical computation algorithm that is based on a planar resonator model for the individual Josephson tunnel junctions is used to calculate the DC current density distribution. In addition to the fundamental microwave frequency, harmonic contents of the tunneling current are also considered. The lateral dimensions of the individual junctions are small compared to the microwave wavelength and the Josephson penetration depth, giving an almost constant current density distribution. Therefore, the coupled junctions can give much greater step amplitudes than a single junction with an equal tunneling area, because of their nonuniform current density distribution. The calculation show a strong dependence of the Shapiro step amplitudes with respect to the coupling of the tunnel junctions. These studies imply that the choice of proper coupling conditions is important to achieve maximum step amplitudes. These results are helpful in designing tunnel junctions with optimized step amplitudes.