This article is cited in 5 papers

CONDENSED MATTER

Temperature sensitivity and noise of an HTSC Josephson detector on a sapphire bicrystal substrate at 77 K

M. A. Tarasov^a, E. Stepantsov^b, A. Kalabukhov^c, M. Yu. Kupriyanov^d, D. Vinkler<sup>c

a</sup> Kotel'nikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences
^b Institute of Cristallography RAS
^c Chalmers University of Technology, Gothenburg SE41296, Sweden
^d Institute of Nuclear Physics, Moscow State University

Abstract: In YBa₂Cu₃O_{7 − x} films grown on sapphire bicrystal substrates, the Josephson junctions are prepared based on artificial grain boundaries formed by the turn of the crystal lattices about the [100] axis. The films are deposited by the laser ablation method on the buffer CeO₂ layer. The critical film temperature reaches 88.5 K with a transition width of 1.5 K. Junctions from 2 to 3-μ m wide are integrated into the planar log-periodic antennas and their characteristics are measured at 77 K. The characteristic voltage I _c R _n reaches 570 μV. With exposure to external radiation at a frequency of 113 GHz, the Shapiro steps were observed on the current-voltage characteristic. The temperature sensitivity of this detector placed in a quasi-optical receiving unit is measured. At the modulation of the input radiation temperature 77 K/300 K, a response of more than 200 nV is observed at the detector output. At the modulation frequency, intrinsic noise is about 1 nV/Hz^1/2, which corresponds to a temperature resolution of 1 K.

PACS: 74.50.+r, 85.25.Pb

Received: 11.10.2007
Revised: 22.10.2007

 English version: Journal of Experimental and Theoretical Physics Letters, 2007, 86:11, 718–720

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