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Author Aksaev, E. E.; Gershenzon, E. M.; Gershenson, M. E.; Goltsman, G. N.; Semenov, A. D.; Sergeev, A. V. url  openurl
  Title Prospects for using high-temperature superconductors to create electron bolometers Type Journal Article
  Year 1989 Publication Pisma v Zhurnal Tekhnicheskoi Fiziki Abbreviated Journal Pisma v Zhurnal Tekhnicheskoi Fiziki  
  Volume 15 Issue 14 Pages 88-93  
  Keywords (up) HTS HEB  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Russian Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0320-0116 ISBN Medium  
  Area Expedition Conference  
  Notes Перспективы применения высокотемпературных сверхпроводников для создания электронных болометров Approved no  
  Call Number Serial 1693  
Permanent link to this record
 

 
Author Darula, Marian; Semenov, Alex D.; Hübers, Heinz-Wilhelm; Schubert, Josef url  openurl
  Title Quasioptical high-Tc superconductor Josephson mixer at terahertz frequencies Type Abstract
  Year 2000 Publication Proc. 11th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 11th Int. Symp. Space Terahertz Technol.  
  Volume Issue Pages 515  
  Keywords (up) HTS Josephson mixers  
  Abstract Mixers based on Josephson junctions from conventional superconductor materials have demonstrated excellent performance at subgap frequencies. The advantages of Josephson mixers are low optimal power of the local oscillator and large intermediate frequency bandwidth but their noise temperature increases dramatically at frequencies corresponding to the energy gap of the superconductor, which is typically below 1 THz for widely used materials. The large energy gap of oxide superconductors makes them promising candidates for development of terahertz Josephson mixers. Here we report on experimental study of the quasioptical mixer utilizing bicrystal Josephson junction from high-transition-temperature YBa 2 Cu 3 O 7-δ film. Junctions with a width of 2 µm were fabricated from 100 nm thick laser ablated films on bicrystal MgO substrates and had the and the J C R n product of about 2 mV at 4.2 K. The planar complementary logarithmic spiral antenna incorporated into co-planar waveguide was patterned from 200 nm thick gold film thermally evaporated in situ on top of the YBa 2 Cu 3 O 7-δ film. The mixer chip was clamped to the extended hemispherical silicon lens. Performance of the mixer was investigated at 4.5 K bath temperature. We used FIR laser as a local oscillator at frequencies 0.698 and 2.52 THz. System noise temperature (DSB) was determined from Y-factor measured with 300 K and 77 K loads. At 0.698 THz the lowest noise temperature 1750 K was observed when the mixer was biased with the fixed current to the region in the vicinity of either the first Shapiro step or the critical current. Between these two bias points the noise temperature increased to ≈ 20000 K. As function of the local oscillator power the noise temperature reached the minimum when the critical current was suppressed to the half of its equilibrium value. Power of the local oscillator absorbed by the mixer at optimal operation was of the order 100 nW. The present design of our antenna limits the upper operation frequency to the value of 1.8 THz. Nevertheless, we clearly observed Shapiro steps at the frequency 2.52 THz. Bearing in mind an improved design of the antenna, we estimate the 3000 K DSB noise temperature at this frequency.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
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  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1555  
Permanent link to this record
 

 
Author Sergeev, A. V.; Livanov, D. V. url  doi
openurl 
  Title Phonon renormalization of thermoelectric power of high-Tc materials Type Conference Article
  Year 1993 Publication Phonon Scattering in Condensed Matter VII. Springer Series in Solid-State Sciences Abbreviated Journal Phonon Scattering in Condensed Matter VII. Springer Series in Solid-State Sciences  
  Volume 112 Issue Pages 204-205  
  Keywords (up) HTS, YBCO  
  Abstract Renormalization of thermoelectric power due to Nielsen — Taylor effect (interference between electron-phonon and electron- impurity interactions) is used for the explanation of the temperature dependence and sign of the thermopower in high-Tc materials. In the framework of the model the negative sign of TEP of untwinned YBa2Cu3O7−x crystal in a-direction observed by Howson et. al. is connected to the strong hole scattering via O-vacancies in chains.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor Meissner, M.; Pohl, R. O.  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference Seventh International Conference, Cornell University, Ithaca, New York, August 3-7, 1992  
  Notes Approved no  
  Call Number Serial 1664  
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Author Gershenzon, E. M.; Gol'tsman, G. N.; Potapov, V. D.; Sergeev, A. V. url  doi
openurl 
  Title Restriction of microwave enhancement of superconductivity in impure superconductors due to electron-electron interaction Type Journal Article
  Year 1991 Publication Phys. B Condens. Mat. Abbreviated Journal Phys. B Condens. Mat.  
  Volume 169 Issue 1-4 Pages 629-630  
  Keywords (up) impure superconductors  
  Abstract Transition from microwave enhancement of supercurrent to superconductivity suppression is investigated in impure superconductors. It is demonstrated that frequency range of enhancement effect narrows with the decrease of electron mean free path, ℓ, and at ℓ⩽1nm 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.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0921-4526 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1682  
Permanent link to this record
 

 
Author Gershenzon, E. M.; Gol'tsman, G. N.; Potapov, V. D.; Sergeev, A. V. url  doi
openurl 
  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 (up) 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.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0038-1098 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1687  
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