Records |
Author |
Varyukhin, S. V.; Zakharov, A. A.; Gershenzon, E. M.; Gol'tsman, G. N.; Ptitsina, N. G.; Chulkova, G. M. |
Title |
Low energy excitation in La2CuO4 |
Type |
Journal Article |
Year |
1990 |
Publication |
Sverkhprovodimost': Fizika, Khimiya, Tekhnika |
Abbreviated Journal |
Sverkhprovodimost': Fizika, Khimiya, Tekhnika |
Volume |
3 |
Issue |
5 |
Pages |
832-837 |
Keywords |
metal-dielectric-La2CuO4, monocrystals |
Abstract |
Measurements of transmission and photoconductivity spectra in submillimeter wave length range as well as of capacity C and conductivity G in the region of acoustic frequencies of metal-dielectric-La2CuO4 system at low temperatures are performed using La2CuO4 monocrystals. Optical spectra posses a threshold character, a sharp decrease of transmission and photocoductivity signal occurs in the energy region hν>1.5 MeV. C(ω,T) and G(ω, T) dependences have a universal form typical of Debye type relaxation processes. Relaxation time dependence is of thermoactivated character τ(T)∼exp(ξ/T) with the gap value ξ≅2 meV. It is assumed that excitations with characteristic energy of ∼2 meV exist in La2CuO4. A possible nature of the detected low-energy excitations is discussed. |
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1688 |
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Author |
Gershenzon, E. M.; Gol’tsman, G. N.; Sergeev, A.; Semenov, A. D. |
Title |
Picosecond response of YBaCuO films to electromagnetic radiation |
Type |
Conference Article |
Year |
1990 |
Publication |
Proc. European Conf. High-Tc Thin Films and Single Crystals |
Abbreviated Journal |
Proc. European Conf. High-Tc Thin Films and Single Crystals |
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Pages |
457-462 |
Keywords |
YBCO HTS detectors |
Abstract |
Radiation-induced change of the resistance was studied in the resistive state of YBaCuO films. Electron-phonon relaxation time T h was determmed from direct ep measurements and analysis of quasistationary electron heating. Temperature dependence of That TS 40 K was found to – ep be T h.. T'. The resul ts show that ep detectors with the response time of few picosecond at nitrogen temperature can be realized. |
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Gorzkowski, W.; Gutowski, M.; Reich, A.; Szymczak, H. |
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European Conference , Ustroń, Poland , 30 Sept – 4 Oct 1989 |
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1695 |
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Author |
Gershenzon, E. M.; Gershenzon, M. E.; Goltsman, G. N.; Semenov, A. D.; Sergeev, A. V. |
Title |
Wide-band highspeed Nb and YBaCuO detectors |
Type |
Journal Article |
Year |
1991 |
Publication |
IEEE Trans. Magn. |
Abbreviated Journal |
IEEE Trans. Magn. |
Volume |
27 |
Issue |
2 |
Pages |
2836-2839 |
Keywords |
YBCO, HTS, Nb detectors |
Abstract |
The physical limitations on the response time and the nature of nonequilibrium detection of radiation were investigated for Nb and YBCO film in a wide spectral range from millimeter to near-infrared wavelengths. In the case of ideal heat removal from the film, the detection mechanism is connected with an electron heating effect which is not selective over a wide spectral interval. For Nb, the dependence of the response time on the electron mean free path l and temperature T is tau varies as T/sup -2/l/sup -1/. The values of detectivity D* and tau are 3*10/sup 11/ W/sup -1/ Hz/sup 1/2/ cm and 5*10/sup -9/ s at T=1.6 K, respectively. For YBCO film the tau value of 1-2 ps at T=77 K was obtained; the NEP value of 3*10/sup -11/ W-Hz/sup -1/2/ can be obtained at T=77 K in the case of the optimal film matching to the radiation. |
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0018-9464 |
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239 |
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Gol'tsman, G. N.; Semenov, A. D.; Gousev, Y. P.; Zorin, M. A.; Gogidze, I. G.; Gershenzon, E. M.; Lang, P. T.; Knott, W. J.; Renk, K. F. |
Title |
Sensitive picosecond NbN detector for radiation from millimetre wavelengths to visible light |
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Journal Article |
Year |
1991 |
Publication |
Supercond. Sci. Technol. |
Abbreviated Journal |
Supercond. Sci. Technol. |
Volume |
4 |
Issue |
9 |
Pages |
453-456 |
Keywords |
NbN HEB detectors |
Abstract |
The authors report on the application of a broad-band NbN film detector which has high sensitivity and picosecond response time for detection of radiation from millimetre wavelengths to visible light. From a study of amplitude modulated radiation of backward-wave tubes and picosecond pulses from gas and solid state lasers at wavelengths between 2 mm and 0.53 mu m, they found a detectivity of 1010 W-1 cm Hz-1/2 and a response time of less than 50 ps at T=10 K. The characteristics were provided by using a 150 AA thick NbN film patterned into a structure of micron strips. According to the proposed detection mechanism, namely electron heating, they expect an intrinsic response time of approximately 20 ps at the same temperature. |
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0953-2048 |
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242 |
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Author |
Gershenzon, E. M.; Gol’tsman, G. N.; Gousev, Y. P.; Elant’ev, A. I.; Semenov, A. D. |
Title |
Electromagnetic radiation mixer based on electron heating in resistive state of superconductive Nb and YBaCuO films |
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Journal Article |
Year |
1991 |
Publication |
IEEE Trans. Magn. |
Abbreviated Journal |
IEEE Trans. Magn. |
Volume |
27 |
Issue |
2 |
Pages |
1317-1320 |
Keywords |
YBCO, HTS, Nb HEB mixers |
Abstract |
A theory of an electron-heating mixer which makes it possible to calculate all the characteristics of the device is developed. It is shown that positive conversion gain is possible for such a mixer in the millimeter to near-infrared wavelength range. The dynamic range and the optimum heterodyne power can be selected from a very wide interval by varying the mixing element volume. Measurements made for Nb within the frequency range of 120-750 GHz confirm the theory. The conversion loss obtained at T=1.6 K and normalized to the element reaches 0.3 dB in the intermediate frequency band of 40 MHz; the possible noise temperature is 50 K. The estimation of noise temperature and output band for YBaCuO at T=77 yields 200 K and more than 10 GHz, respectively. |
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1941-0069 |
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1681 |
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