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Author Samsonova, Alena; Zolotov, Philipp; Baeva, Elmira; Lomakin, Andrey; Titova, Nadezhda; Kardakova, Anna; Goltsman, Gregory
Title Signatures of surface magnetic disorder in thin niobium films Type Journal Article
Year 2021 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal
Volume Issue (up) Pages 1-1
Keywords Temperature measurement, Temperature dependence, Superconducting magnets, Superconducting transition temperature, Substrates, Resistance, Scattering
Abstract We present our studies on the evolution of the normal and superconducting properties with thickness of thin Nb films with a low level of non-magnetic disorder (kFl 150 for the thickest film in the set). The analysis of the superconducting behavior points to the presence of magnetic moments, hidden in the native oxide on the surface of Nb films. Using the Abrikosov-Gorkov theory, we obtain the density of surface magnetic moments of 1013 cm-2, which is in agreement with the previously reported data for Nb films.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1051-8223 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1162
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Author Semenov, A.; Richter, H.; Hübers, H.-W.; Smirnov, K.; Voronov, B.; Gol'tsman, G.
Title Development of terahertz superconducting hot-electron bolometer mixers Type Conference Article
Year 2003 Publication Proc. 6th European Conf. Appl. Supercond. Abbreviated Journal Proc. 6th European Conf. Appl. Supercond.
Volume 181 Issue (up) Pages 2960-2965
Keywords NbN HEB mixers
Abstract We present recent results of the development of phonon cooled hot-electron bolometric (HEB) mixers for airborne and balloon borne terahertz heterodyne receivers. Three iomportant issues have been addresses: the quality of NbN films the HEB mixers were made from, the spectral properties of the HEB mixers and the local oscillator power required for optical operation. Studies with an atomic force microscope indicate, that the performance of the HEB mixer might have been effected by the microstructure of the NbN film. Antenna gain and noise temperature were investigated at terahertz frequencies for a HEB embedded in either log-spiral or twin-slot feed antenna. Comparison suggests that at frequencies above 3 THz the spiral feed provides better overall performance. At 1.6 THz, a power of 2.5 µW was required from the local oscillator for optimal operation of the HEB mixer.
Address Sorrento, Italy
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 ISBN 0750309814, 978-0750309813 Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1505
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Author Semenov, A. D.; Sergeev, A. V.; Kouminov, P.; Goghidze, I. G.; Heusinger, M. A.; Nebosis, R. S.; Gol'tsman, G. N.; Gershenzon, E. M.; Renk, K. F.
Title Transparency of YBCO film/substrate interfaces for thermal phonons determined by photoresponse measurements Type Conference Article
Year 1993 Publication Proc. 1st European Conf. on Appl. Supercond. Abbreviated Journal Proc. 1st European Conf. on Appl. Supercond.
Volume 2 Issue (up) Pages 1443-1446
Keywords YBCO HTS detectors
Abstract Direct measurements of the thermal boundary resistance were performed by means of the stationary method. In this approach the temperature of an electrically heated film is controlled by its dc resistance while an additional film on the same substrate is used as a thermometer monitoring substrate temperature. The temperature field in the substrate is then calculated to deduce the Kapitza temperature step at the interface between the heated strip and the substrate. The main statement of all afore-said papers is that experimental values of the thermal boundary resistance are too large to be explained by the acoustic mismatch model. In this paper we investigate transparency of YBaCuO film/substrate interfaces for thermal phonons by means of photoresponse measurements. We show that our data are in reasonable agreement with the acoustic mismatch theory.
Address
Corporate Author Thesis
Publisher Place of Publication Editor Freyhardt, H. C.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN 3-88355-197-X Medium
Area Expedition Conference 1st European conference on applied superconductivity
Notes Approved no
Call Number Serial 1661
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Author Kroug, M.; Cherednichenko, S.; Merkel, H.; Kollberg, E.; Voronov, B.; Gol'tsman, G.; Hübers, H. W.; Richter, H.
Title NbN hot electron bolometric mixers for terahertz receivers Type Journal Article
Year 2001 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 11 Issue (up) 1 Pages 962-965
Keywords NbN HEB mixers
Abstract Sensitivity and gain bandwidth measurements of phonon-cooled NbN superconducting hot-electron bolometer mixers are presented. The best receiver noise temperatures are: 700 K at 1.6 THz and 1100 K at 2.5 THz. Parylene as an antireflection coating on silicon has been investigated and used in the optics of the receiver. The dependence of the mixer gain bandwidth (GBW) on the bias voltage has been measured. Starting from low bias voltages, close to operating conditions yielding the lowest noise temperature, the GBW increases towards higher bias voltages, up to three times the initial value. The highest measured GBW is 9 GHz within the same bias range the noise temperature increases by a factor of two.
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ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 312
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Author Shitov, S. V.; Levitchev, M.; Veretennikov, A. V.; Koshelets, V. P.; Prokopenko, G. V.; Filippenko, L. V.; Ermakov, A. B.; Shtanyuk, A. M.; Kohlstedt, H.; Ustinov, A. V.
Title Superconducting integrated receiver as 400-600 GHz tester for coolable devices Type Journal Article
Year 2001 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal
Volume 11 Issue (up) 1 Pages 832-835
Keywords
Abstract
Address
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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Area Expedition Conference
Notes Approved no
Call Number RPLAB @ s @ sis_Shitov_2001 Serial 313
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