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Author Gershenzon, E. M.; Gol'tsman, G. N.; Semenov, A. D.; Sergeev, A. V.
Title Mechanism of picosecond response of granular YBaCuO films to electromagnetic radiation Type Journal Article
Year 1990 Publication Solid State Communications Abbreviated Journal Solid State Communications
Volume 76 Issue 4 Pages 493-497
Keywords YBCO HTS detectors
Abstract The ultrafast mechanisms of radiation detection in granular YBaCuO films are studied in the wide wavelength range from millimeter to near infrared. With the rise of radiation frequency the Josephson detection at the grain boundary weak links is replaced by electron heating into the grains. This change occurs in the submillimeter wavelength range. Electron-phonon relaxation time τeph is determined by direct measurements and analyses quasistationary electron heating. Temperature dependence of τeph at T ≤ 40 K was found to be τeph ∼ T−1. The results show that detectors with the response time of few picoseconds at nitrogen temperature are attainable.
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Language Summary Language Original Title
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ISSN (down) 0038-1098 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1685
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Author Gershenzon, E. M.; Gol'tsman, G. N.; Potapov, V. D.; Sergeev, A. V.
Title Restriction of microwave enhancement of superconductivity in impure superconductors due to electron-electron interaction Type Journal Article
Year 1990 Publication Solid State Communications Abbreviated Journal Solid State Communications
Volume 75 Issue 8 Pages 639-641
Keywords impure superconductors
Abstract Transition from microwave enhancement of supercurrent to superconductivity suppression is investigated in impure superconductors. It is demonstrated that the frequency range of the enhancement effect narrows with the decrease of the electron mean free path, l, and at l ⩽ 1 nm electron heating is observed in the whole frequency range. Dependences of frequency boundaries on l are explained by taking into account strong electron-electron interaction in impure metals.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 0038-1098 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1687
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Author Gershenzon, E. M.; Gol'tsman, G. N.; Semenov, A. D.
Title Submillimeter backward wave tube spectrometer for measuring superconducting film transmission Type Journal Article
Year 1983 Publication Pribory i Tekhnika Eksperimenta Abbreviated Journal Pribory i Tekhnika Eksperimenta
Volume 26 Issue 5 Pages 134-137
Keywords BWO spectroscopy, spectrometer, transmission
Abstract A spectrometer employing six backward wave tubes is described. It is intended for investigation of superconductors in the 0.2-3 mm range of wave lengths. During the measurement of the transmission spectrum it is possible to determine the energy gap for superconduct1ng films 50 to 4000 A thick. The transmission factor can vary from 10-1 to 10-9. Spectrum of relation of film transmission factors in superconducting and normal states is measured for determining the energy gap 2 Δ. The transmission spectrum obtained by means of a computer for vanadium film 300 A thick is given as an example. The energy gap 2 Δ = 1.4 MeV
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Language Russian Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 0032-8162 ISBN Medium
Area Expedition Conference
Notes Субмиллиметровый спектрометр с лампами обратной волны для измерения пропускания сверхпроводниковых пленок Approved no
Call Number Serial 1713
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Author Semenov, A. D.; Hübers, H.-W.; Schubert, J.; Gol'tsman, G. N.; Elantiev, A. I.; Voronov, B. M.; Gershenzon, E. M.
Title Design and performance of the lattice-cooled hot-electron terahertz mixer Type Journal Article
Year 2000 Publication J. Appl. Phys. Abbreviated Journal J. Appl. Phys.
Volume 88 Issue 11 Pages 6758-6767
Keywords HEB mixer, charge imbalance, HF current distribution
Abstract We present the measurements and the theoreticalmodel of the frequency-dependent noise temperature of a superconductor lattice-cooled hot-electron bolometer mixer in the terahertz frequency range. The increase of the noise temperature with frequency is a cumulative effect of the nonuniform distribution of the high-frequency current in the bolometer and the charge imbalance, which occurs at the edges of the normal domain and at the contacts with normal metal. We show that under optimal operation the fluctuation sensitivity of the mixer is determined by thermodynamic fluctuations of the noise power, whereas at small biases there appears additional noise, which is probably due to the flux flow. We propose the prescription of how to minimize the influence of the current distribution on the mixer performance.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 0021-8979 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 306
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Author Karasik, B. S.; Zorin, M. A.; Milostnaya, I. I.; Elantev, A. I.; Gol’tsman, G. N.; Gershenzon, E. M.
Title Subnanosecond switching of YBaCuO films between superconducting and normal states induced by current pulse Type Journal Article
Year 1995 Publication J. Appl. Phys. Abbreviated Journal J. Appl. Phys.
Volume 77 Issue 8 Pages 4064-4070
Keywords YBCO HTS switches
Abstract A study is reported of the current switching in high‐quality YBaCuO films deposited onto NdGaO3 and ZrO2 substrates between superconducting (S) and normal (N) states. The films 60–120 nm thick prepared by laser ablation were structured into single strips between gold contacts. The time dependence of the resistance after application of the voltage step to the film was monitored. Experiment performed within certain ranges of voltage amplitudes and temperatures has shown the occurrence of the fast stage (shorter than 400 ps) both in S‐N and N‐S transitions. A fraction of the film resistance changing within this stage in the S‐N transition increases with the current amplitude. A subnanosecond N‐S stage becomes more pronounced for shorter pulses. The fast switching is followed by the much slower change of resistance. The mechanism of switching is discussed in terms of the hot‐electron phenomena in YBaCuO. The contributions of other thermal processes (e.g., a phonon escape from the film, a heat diffusion in the film and substrate, a resistive domain formation) in the subsequent stage of the resistance dynamic have been also discussed. The basic limiting characteristics (average dissipated power, energy needed for switching, maximum repetition rate) of a picosecond switch which is proposed to be developed are estimated.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN (down) 0021-8979 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1623
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