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

Near-millimeter-wave response of high T c ramp-type Josephson junctions

R. Gupta, Qing Hu, D. Terpstra, G.J. Gerritsma, Horst Rogalla

Published Jun 21, 1993• 10 citations
Publisher

Abstract

We have studied the response of a YBCO/PBCO/YBCO ramp-type junction to coherent radiation at 176 and 270 GHz. The I-V characteristic of the junction closely resembles the prediction of the RSJ model. The IcRn product of the junction is 0.25 mV at 5 K. The millimeter-wave radiation is coupled to the junction via a quasioptical structure that focuses the radiation onto the junction through a yttrium-stabilized ZrO2 substrate. At 176 GHz, we have observed as many as six Shapiro steps at the maximum power level of our Gunn oscillator-pumped frequency doubler. Shapiro steps are still clearly seen up to 65 K. The amplitudes of the zeroth, first, and second Shapiro steps, as functions of the square root of the radiation power, agree remarkably well with a Bessel function fit, indicating the junction is voltage-biased at the radiation frequency (rf). At 270 GHz, due to a combination of the heavy rf loss in the ZrO2 substrate and the lack of radiation power, we have observed only the first Shapiro step.

DOI
10.1063/1.109068

Related papers

Noise study of a high-T c Josephson junction under near-millimeter-wave irradiation

R. Gupta, Qing Hu, D. Terpstra +2 more

Noise studies of both the dc and ac Josephson effects have been performed on a high-Tc ramp-type Josephson junction irradiated at 176 GHz. Well-established analytical results for noise in overdamped RSJs are used to model the measured I-V characteristics, and their agreement is excellent. Noise-rounded I-V curves at the critical current and the first and second Shapiro steps under coherent 176 GHz radiation have been studied in detail at several temperatures and rf power levels. The noise temperatures inferred from these simulations are close to the physical temperatures. An increase of noise temperatures at high radiation power levels is a result of radiation heating, which could be due to a bolometric effect.

Applied Physics Letters•Feb 14, 1994•8 citations

Millimeter and submillimeter wave responses of YBa/sub 2/Cu/sub 3/O/sub 7/ step-edge Josephson junctions

Hisashi Shimakage, Yoshinori Uzawa, Z. Wang +3 more

We have fabricated YBCO step-edge Josephson junctions and measured the responses to millimeter and submillimeter irradiation. In the substrate milling process for the purpose of fabricating the step, the step angle was controlled using a Nb metal mask. At a step angle of 20 degrees, we obtained Josephson junctions, the characteristics of which are consistent with the RSJ model. We estimated the capacitance to be 4.4 fF using the RSJ model, but such a value for an 8 /spl mu/m wide and 300 nm thick junction seems too small. When the junctions were irradiated by 300 GHz radiation, Shapiro steps up to the 4th were observed. The junctions were used as mixers in the 100 GHz band, and as harmonic mixers in the 100 GHz LO and 700 GHz RF bands. Beat signals were observed in both cases. We also estimated the quasi-optical conversion losses of the step-edge junctions as mixers.>

IEEE Transactions on Applied Superconductivity•Jun 1, 1995•13 citations

On and off-chip detection of radiation from HTS Josephson junction arrays

Kiejin Lee, Ienari Iguchi, K. Y. Constantinian

We have investigated the mutual phase interaction between a single detector junction and a phase-locked three-junction array of high-T/sub c/ Josephson junctions. The YBCO Josephson junctions were fabricated on a MgO bicrystal substrate. In the array junction structure, the dc bias current was fed to the junction array having parallel geometry with each pair of junctions shunted by a superconducting coplanar microstrip superconducting loop. The configuration of bias leads was a series connection of interlocking dc SQUIDs geometry which enables all junctions to oscillate at the same frequency. We measured the radiation power of a Josephson-junction array using an off-chip coupled to a radiometer and on-chip coupled to a single junction from centimeter- to millimeter-wave ranges. Clear self-induced Shapiro steps were observed in the current-voltage curves of the detector junction. The power transfered to the single detector junction was estimated from the modulation of Shapiro step height. The maximum detected power level was about 7 nW at frequency 150-250 GHz. The Josephson oscillation power excited the resonant mode coupled to the coplanar microstrip loops.

IEEE Transactions on Applied Superconductivity•Jun 1, 1999•1 citation

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

Millimeter and submillimeter wave responses of YBa2Cu307 step-edge Josephson junctions

Hisashi Shimakage, Yoshinori Uzawa, Z. Wang +3 more

We have fabricated YBCO step-edge Josephson junctions and measured the responses to the millimeter and submillimeter irradiation. In the substrate milling process for the purpose of fabricat- ing the step, the step angle was controlled using a Nb metal mask. At a step angle of 20 degrees, we obtained Josephson junctions, the characteristics of which are consistent with the RSJ model. We estimated the ca- pacitance to be 4.4 fF using the RSJ model, but such a value for an 8 pm wide and 300 nm thick junction seems too small. When the junctions were irradiated by 300 GHz, Shapiro steps up to the 4th were ob- served. The junctions were used as mixers in the 100 GHz band, and as harmonic mixers in the 100 GHz LO and 700 GHz RF bands. Beat signals were observed in both cases. We also estimated the quasi-optical con- version losses of the stepedge junctions as mixers.

•Jan 1, 1995•0 citations

Dynamic range of frequency-selective response of high-T/sub c/ Josephson detector to millimeter-wave radiation

V.V. Shirotov, Yu. Ya. Divin, Knut W. Urban

We have studied a voltage dependence of the response /spl Delta/I(V) of high-T/sub c/ Josephson detector to millimeter-wave radiation as a function of power of incident radiation. YBa/sub 2/Cu/sub 3/O/sub 7-x/ grain-boundary junctions with the resistances R/sub n/=0.5-1.5 Ohm and the I/sub c/R/sub n/-product in the range 0.16-0.25 mV at 80 K have been fabricated for this study. Gunn oscillator with the frequency f=86 GHz and a set of calibrated attenuators with total attenuation of 80 dB have been used for the measurements. The dynamic range, i.e. the range of power of electromagnetic radiation at which the response of the detector is directly proportional to radiation power, was found to be around 40 dB above the noise-equivalent power for frequency-selective response at voltages V near hf/2e and >45 dB for the broadband response at low voltages.

IEEE Transactions on Applied Superconductivity•Mar 1, 2001•4 citations
We have studied the response of a YBCO/PBCO/YBCO ramp-type junction to coherent radiation at 176 and 270 GHz. The I-V characteristic of the junction closely resembles the prediction of the RSJ model. The IcRn product of the junction is 0.25 mV at 5 K. The millimeter-wave radiation is coupled to the junction via a quasioptical structure that focuses the radiation onto the junction through a yttrium-stabilized ZrO2 substrate. At 176 GHz, we have observed as many as six Shapiro steps at the maximum power level of our Gunn oscillator-pumped frequency doubler. Shapiro steps are still clearly seen up to 65 K. The amplitudes of the zeroth, first, and second Shapiro steps, as functions of the square root of the radiation power, agree remarkably well with a Bessel function fit, indicating the junction is voltage-biased at the radiation frequency (rf). At 270 GHz, due to a combination of the heavy rf loss in the ZrO2 substrate and the lack of radiation power, we have observed only the first Shapiro step.
Noise studies of both the dc and ac Josephson effects have been performed on a high-Tc ramp-type Josephson junction irradiated at 176 GHz. Well-established analytical results for noise in overdamped RSJs are used to model the measured I-V characteristics, and their agreement is excellent. Noise-rounded I-V curves at the critical current and the first and second Shapiro steps under coherent 176 GHz radiation have been studied in detail at several temperatures and rf power levels. The noise temperatures inferred from these simulations are close to the physical temperatures. An increase of noise temperatures at high radiation power levels is a result of radiation heating, which could be due to a bolometric effect.
We have fabricated YBCO step-edge Josephson junctions and measured the responses to millimeter and submillimeter irradiation. In the substrate milling process for the purpose of fabricating the step, the step angle was controlled using a Nb metal mask. At a step angle of 20 degrees, we obtained Josephson junctions, the characteristics of which are consistent with the RSJ model. We estimated the capacitance to be 4.4 fF using the RSJ model, but such a value for an 8 /spl mu/m wide and 300 nm thick junction seems too small. When the junctions were irradiated by 300 GHz radiation, Shapiro steps up to the 4th were observed. The junctions were used as mixers in the 100 GHz band, and as harmonic mixers in the 100 GHz LO and 700 GHz RF bands. Beat signals were observed in both cases. We also estimated the quasi-optical conversion losses of the step-edge junctions as mixers.>
We have investigated the mutual phase interaction between a single detector junction and a phase-locked three-junction array of high-T/sub c/ Josephson junctions. The YBCO Josephson junctions were fabricated on a MgO bicrystal substrate. In the array junction structure, the dc bias current was fed to the junction array having parallel geometry with each pair of junctions shunted by a superconducting coplanar microstrip superconducting loop. The configuration of bias leads was a series connection of interlocking dc SQUIDs geometry which enables all junctions to oscillate at the same frequency. We measured the radiation power of a Josephson-junction array using an off-chip coupled to a radiometer and on-chip coupled to a single junction from centimeter- to millimeter-wave ranges. Clear self-induced Shapiro steps were observed in the current-voltage curves of the detector junction. The power transfered to the single detector junction was estimated from the modulation of Shapiro step height. The maximum detected power level was about 7 nW at frequency 150-250 GHz. The Josephson oscillation power excited the resonant mode coupled to the coplanar microstrip loops.
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 YBCO step-edge Josephson junctions and measured the responses to the millimeter and submillimeter irradiation. In the substrate milling process for the purpose of fabricat- ing the step, the step angle was controlled using a Nb metal mask. At a step angle of 20 degrees, we obtained Josephson junctions, the characteristics of which are consistent with the RSJ model. We estimated the ca- pacitance to be 4.4 fF using the RSJ model, but such a value for an 8 pm wide and 300 nm thick junction seems too small. When the junctions were irradiated by 300 GHz, Shapiro steps up to the 4th were ob- served. The junctions were used as mixers in the 100 GHz band, and as harmonic mixers in the 100 GHz LO and 700 GHz RF bands. Beat signals were observed in both cases. We also estimated the quasi-optical con- version losses of the stepedge junctions as mixers.
We have studied a voltage dependence of the response /spl Delta/I(V) of high-T/sub c/ Josephson detector to millimeter-wave radiation as a function of power of incident radiation. YBa/sub 2/Cu/sub 3/O/sub 7-x/ grain-boundary junctions with the resistances R/sub n/=0.5-1.5 Ohm and the I/sub c/R/sub n/-product in the range 0.16-0.25 mV at 80 K have been fabricated for this study. Gunn oscillator with the frequency f=86 GHz and a set of calibrated attenuators with total attenuation of 80 dB have been used for the measurements. The dynamic range, i.e. the range of power of electromagnetic radiation at which the response of the detector is directly proportional to radiation power, was found to be around 40 dB above the noise-equivalent power for frequency-selective response at voltages V near hf/2e and >45 dB for the broadband response at low voltages.