J. Phys. III France
Volume 4, Numéro 4, April 1994
Page(s) 635 - 640
DOI: 10.1051/jp3:1994153
J. Phys. III France 4 (1994) 635-640

Modelization and experiments on high $T_{\rm c}$ superconducting bolometers in the 10-90 K range of temperature

Pierre Langlois1, Christophe Dolabdjian1, Didier Robbes1, Daniel Bloyet1, Jean-François Hamet2, Eric Mossang3 and Olivier Thomas3

1  LEI, ISMRA, Université de Caen, Bd Mal Juin, F 14050 Caen Cedex, France
2  CRISMAT, CNRS 1318-ISMRA, Université de Caen, Bd Mal Juin, F 14050 Caen Cedex, France
3  LMGP-ENSPG, URA CNRS - 1109, BP 46, F 38602 St Martin d'Hères, France

(Received 15 July 1993, accepted 9 November 1993)

As previously reported, the critical current $I_{\rm c}$ dependence versus optical power P in the mW range at 780 nm, with P focused on microbridges of YBCO thin films, can be calculated using simple assumptions on heat production in the superconducting film and heat conduction to the substrate. For the model was only valid on a limited range of temperature T where the thermal boundary resistance $R_{\rm bd}$ lying at the film-substrate interface could be taken as a constant R0 = 10-3 K cm 2/W, we present a full model obtained by integration of the coupled Fourier equations of the temperature in the superconducting anisotropic YBCO film and in its substrate. We show that the thermal boundary resistance modelized as $R_{\rm bd}(T) = B/T^3 + R_0$, with B/T3 given by the acoustic mismath model, is still limiting the heat transfer from the film to the substrate at least down to 10 K. As a consequence, the simple model that uses only $R_{\rm bd}(T)$ and ${\rm d}I_{\rm c}/{\rm d}T$ is still useful and allows realistic evaluations of the current sensitivity S1(P, T) to the applied power P on the temperature range 10-90 K. Calculated S1(p, T) in the 0.1-1 A/W range agree well with those measured on YBCO/MgO or YBCO/SrTiO 3 devices.

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