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

Applied Physics Letters

Millimeter-wave response and linewidth of Josephson oscillations in YBa2Cu3O7 step-edge junctions

Yu. Ya. Divin, A. V. Andreev, Georg Fischer, J. Mygind, N. F. Pedersen, Klaus Dieter Herrmann, V. N. Glyantsev, M. Siegel, Alex I. Braginski

Published Mar 15, 1993• 18 citations
Publisher

Abstract

We have studied the response of YBa2Cu3O7 step-edge junctions to low-intensity millimeter-wave radiation in the temperature range from 4 to 80 K. The linewidth of the Josephson oscillations derived from the resonant part of the response at voltages V≂(h/2e)f is shown to be determined by thermal fluctuations at liquid nitrogen temperatures. At lower temperatures the observed linewidth increases indicating that low-frequency fluctuations become dominant in the junction as the temperature is reduced. Due to an inhomogeneous spatial distribution of the current the step-edge junction might be considered as a multijunction multiloop interferometer and the excess noise can be discussed in terms of spontaneous transitions between the different states of these interferometers.

DOI
10.1063/1.108712

Related papers

Josephson oscillations and noise temperatures in YBa2Cu3O7−x grain-boundary junctions

Yu. Ya. Divin, J. Mygind, N. F. Pedersen +1 more

The ac Josephson effect was studied in YBa2Cu3O7−x grain-boundary junctions (GBJ) in the temperature range from 4 to 90 K. The temperature dependence of the linewidth of millimeter-wave Josephson oscillations was measured and it is shown that the derived effective noise temperatures may be as low as the physical temperature in the temperature range investigated. In the millimeter-wave range, linewidths as low as 380 MHz were found at liquid-nitrogen temperatures.

Applied Physics Letters•Dec 21, 1992•36 citations

Linewidth of Josephson oscillations in YBa/sub 2/Cu/sub 3/O/sub 7-x/ grain-boundary junctions

Yu. Ya. Divin, J. Mygind, N. F. Pedersen +1 more

The AC Josephson effect in YBa/sub 2/Cu/sub 3/O/sub 7-x/ grain-boundary junctions (GBJs) was studied in the temperature range from 4 K to 90 K. The temperature dependence of the linewidth of millimeter-wave Josephson oscillations was measured, and it is shown that the derived effective noise temperature of GBJ might be as low as the physical temperature in the temperature range investigated. This makes it possible to use the resistively shunted junction (RSJ) model with thermal fluctuations to get a limiting performance of high-T/sub c/ devices utilizing the AC Josephson effect. The lowest value of the linewidth of 72 GHz Josephson oscillations observed at 77 K was equal to 380 MHz, which demonstrates the applicability of GBJ, particularly in the field of radiation spectroscopy, even at liquid nitrogen temperatures.>

IEEE Transactions on Applied Superconductivity•Mar 1, 1993•7 citations

Analysis of Josephson radiation from YBa2Cu3O7thin-film Josephson junctions

Gerhard Kunkel, M Bode, F Wang +4 more

We have investigated the Josephson radiation from different types of YBa 2 Cu 3 O 7 (YBCO) thin-film Josephson junctions: step-edge junctions (SEJs), biepitaxial junctions and SNS junctions with N=Au. The radiation was detected using a non-resonant radiometer system with a receiving frequency of 11-12 GHz. The current-voltage characteristics were measured simultaneously with the radiation spectra in the temperature range 4.2-90 K. All junctions exhibited a large emission peak at a voltage which was related to the frequency through the second Josephson relation. Typically, for high temperatures, and therefore small critical currents, the measured radiation linewidth agreed well with the theoretical predictions. At lower temperatures the experimental linewidths deviated from the theoretical values due to additional noise sources in the junctions. Some of the SEJs showed a non-monotonic dependence of the linewidth on temperature. It is suggested that such SEJ data may be discussed in terms of a model which treats the SEJ as an interferometer consisting of a parallel array of random Josephson junctions.

Superconductor Science and Technology•May 1, 1994•6 citations

Comparison of Josephson radiation properties of different YBa 2 Cu 3 O 7 thin film junctions

Gerhard Kunkel, M. Bode, F. Wang +6 more

We have investigated the Josephson radiation from different types of YBa2Cu3O7 (YBCO) thin film junctions: step-edge (SEJ), biepitaxial, and superconductor-normal conductor- superconductor (SNS) with N=Au and PrBa2Cu3O7. The radiation was detected using a nonresonant radiometer system with a receiving frequency of 11-12 GHz. The current-voltage characteristics were measured simultaneously with the radiation spectra in the temperature range from 4.2 to 90 K. All junctions exhibited a large emission peak at a voltage which was related to the frequency through the second Josephson relation. Typically, for high temperatures, and, therefore, small critical currents, the experimental data of the radiation linewidth agreed well with the theoretical predictions of the RSJ model. At lower temperatures the experimental linewidths deviated from the theoretical values due to additional noise sources in the junctions. Some of the SEJs showed a nonmonotonic dependence of the linewidth on temperature. Such SEJ data will be discussed in terms of a model which treats the SEJ as an interferometer consisting of a parallel array of Josephson junctions.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jul 2, 1994•0 citations

Detection of the Josephson self-radiation from YBCO step-edge junctions in millimeter-wave

K. Lee, Ienari Iguchi

We have investigated both DC and AC Josephson effects of the YBa/sub 2/Cu/sub 3/O/sub y/ (YBCO) thin film step-edge junctions; single step-edge junction on LaAlO/sub 3/ substrate with the step angle about 50-60/spl deg/ and biepitaxial double step-edge junction made on MgO substrate with a CeO/sub 2/ seed layer. The Josephson self-radiation was directly detected using the total power radiometer receiver systems with receiving frequencies of K band (21-23 GHz) and millimeter-wave (46-48 GHz and 71-73 GHz) range, respectively. For single step-edge junctions, the Josephson self-radiation peaks exhibited at the voltages corresponding to the basic Josephson voltage-frequency relation. The maximum first-harmonic self-radiation power at receiving frequency f/sub REC/=72 GHz and Josephson linewidth were P(I)=2.0/spl times/10/sup -3/W and /spl Delta/f=3.62 GHz at 4.2 K, respectively. For microwave irradiation, the harmonic Shapiro steps and additional half integer steps with their quasi-periodic variation satisfying the Josephson equation V=(n/m)(hf/2e) were clearly observed. For double step-edge junctions, we also observed the steps corresponding to the two junction boundaries on the two steep steps. These behaviors described with different current-phase relations corresponding to the crystal orientation relationship between the two junction boundaries.>

IEEE Transactions on Applied Superconductivity•Jun 1, 1995•2 citations

Low-frequency excess noise in SQUIDS with YBa2Cu3O7step-edge junctions

V. N. Glyantsev, M. Siegel, Jürgen Schubert +2 more

We have fabricated RF and DC SQUIDS with step-edge Josephson junctions (SEJ) and YBa 2 Cu 3 O 7 thin films. The low-frequency noise of these SQUIDS has been investigated as a function of temperature, bias current and magnetic field. Typically, the energy resolution in the white noise region of the DC SQUIDS with an inductance of 45 pH was 3*10 -30 J Hz -1 at 77.5 K. Depending on the bias current, the low-frequency spectrum could be of either 1/f type or Lorentzian type. The Lorentzian spectrum was generated by random telegraph signals (RTSS). An Arrhenius plot was obtained from the temperature dependence of the switching time of these RTSS. We have determined two barrier lengths of 0.23 eV and 1 eV of the two-level fluctuator (TLF) generating this RTS noise. From the magnetic-field dependence of the low-frequency noise we have found that the noise is periodic with the flux corresponding to the area of the SEJ. The results were discussed in terms of a model treating the SEJ as a multi-junction interferometer which forms a two-level fluctuator when the junction is placed inside a SQUID loop. The noise is generated by thermally activated switching of the SQUID between the two different states of the SQUID.

Superconductor Science and Technology•May 1, 1994•11 citations
We have studied the response of YBa2Cu3O7 step-edge junctions to low-intensity millimeter-wave radiation in the temperature range from 4 to 80 K. The linewidth of the Josephson oscillations derived from the resonant part of the response at voltages V≂(h/2e)f is shown to be determined by thermal fluctuations at liquid nitrogen temperatures. At lower temperatures the observed linewidth increases indicating that low-frequency fluctuations become dominant in the junction as the temperature is reduced. Due to an inhomogeneous spatial distribution of the current the step-edge junction might be considered as a multijunction multiloop interferometer and the excess noise can be discussed in terms of spontaneous transitions between the different states of these interferometers.
The AC Josephson effect in YBa/sub 2/Cu/sub 3/O/sub 7-x/ grain-boundary junctions (GBJs) was studied in the temperature range from 4 K to 90 K. The temperature dependence of the linewidth of millimeter-wave Josephson oscillations was measured, and it is shown that the derived effective noise temperature of GBJ might be as low as the physical temperature in the temperature range investigated. This makes it possible to use the resistively shunted junction (RSJ) model with thermal fluctuations to get a limiting performance of high-T/sub c/ devices utilizing the AC Josephson effect. The lowest value of the linewidth of 72 GHz Josephson oscillations observed at 77 K was equal to 380 MHz, which demonstrates the applicability of GBJ, particularly in the field of radiation spectroscopy, even at liquid nitrogen temperatures.>
We have investigated the Josephson radiation from different types of YBa 2 Cu 3 O 7 (YBCO) thin-film Josephson junctions: step-edge junctions (SEJs), biepitaxial junctions and SNS junctions with N=Au. The radiation was detected using a non-resonant radiometer system with a receiving frequency of 11-12 GHz. The current-voltage characteristics were measured simultaneously with the radiation spectra in the temperature range 4.2-90 K. All junctions exhibited a large emission peak at a voltage which was related to the frequency through the second Josephson relation. Typically, for high temperatures, and therefore small critical currents, the measured radiation linewidth agreed well with the theoretical predictions. At lower temperatures the experimental linewidths deviated from the theoretical values due to additional noise sources in the junctions. Some of the SEJs showed a non-monotonic dependence of the linewidth on temperature. It is suggested that such SEJ data may be discussed in terms of a model which treats the SEJ as an interferometer consisting of a parallel array of random Josephson junctions.
We have investigated the Josephson radiation from different types of YBa2Cu3O7 (YBCO) thin film junctions: step-edge (SEJ), biepitaxial, and superconductor-normal conductor- superconductor (SNS) with N=Au and PrBa2Cu3O7. The radiation was detected using a nonresonant radiometer system with a receiving frequency of 11-12 GHz. The current-voltage characteristics were measured simultaneously with the radiation spectra in the temperature range from 4.2 to 90 K. All junctions exhibited a large emission peak at a voltage which was related to the frequency through the second Josephson relation. Typically, for high temperatures, and, therefore, small critical currents, the experimental data of the radiation linewidth agreed well with the theoretical predictions of the RSJ model. At lower temperatures the experimental linewidths deviated from the theoretical values due to additional noise sources in the junctions. Some of the SEJs showed a nonmonotonic dependence of the linewidth on temperature. Such SEJ data will be discussed in terms of a model which treats the SEJ as an interferometer consisting of a parallel array of Josephson junctions.
We have investigated both DC and AC Josephson effects of the YBa/sub 2/Cu/sub 3/O/sub y/ (YBCO) thin film step-edge junctions; single step-edge junction on LaAlO/sub 3/ substrate with the step angle about 50-60/spl deg/ and biepitaxial double step-edge junction made on MgO substrate with a CeO/sub 2/ seed layer. The Josephson self-radiation was directly detected using the total power radiometer receiver systems with receiving frequencies of K band (21-23 GHz) and millimeter-wave (46-48 GHz and 71-73 GHz) range, respectively. For single step-edge junctions, the Josephson self-radiation peaks exhibited at the voltages corresponding to the basic Josephson voltage-frequency relation. The maximum first-harmonic self-radiation power at receiving frequency f/sub REC/=72 GHz and Josephson linewidth were P(I)=2.0/spl times/10/sup -3/W and /spl Delta/f=3.62 GHz at 4.2 K, respectively. For microwave irradiation, the harmonic Shapiro steps and additional half integer steps with their quasi-periodic variation satisfying the Josephson equation V=(n/m)(hf/2e) were clearly observed. For double step-edge junctions, we also observed the steps corresponding to the two junction boundaries on the two steep steps. These behaviors described with different current-phase relations corresponding to the crystal orientation relationship between the two junction boundaries.>
We have fabricated RF and DC SQUIDS with step-edge Josephson junctions (SEJ) and YBa 2 Cu 3 O 7 thin films. The low-frequency noise of these SQUIDS has been investigated as a function of temperature, bias current and magnetic field. Typically, the energy resolution in the white noise region of the DC SQUIDS with an inductance of 45 pH was 3*10 -30 J Hz -1 at 77.5 K. Depending on the bias current, the low-frequency spectrum could be of either 1/f type or Lorentzian type. The Lorentzian spectrum was generated by random telegraph signals (RTSS). An Arrhenius plot was obtained from the temperature dependence of the switching time of these RTSS. We have determined two barrier lengths of 0.23 eV and 1 eV of the two-level fluctuator (TLF) generating this RTS noise. From the magnetic-field dependence of the low-frequency noise we have found that the noise is periodic with the flux corresponding to the area of the SEJ. The results were discussed in terms of a model treating the SEJ as a multi-junction interferometer which forms a two-level fluctuator when the junction is placed inside a SQUID loop. The noise is generated by thermally activated switching of the SQUID between the two different states of the SQUID.