Title :
Optical diagnostics for fabrication of YBCO thin film DC SQUIDs
Author :
Obraztsov, A.N. ; Maresov, A.G. ; Vengrus, I.I. ; Snigirev, O.V. ; Krasnosvobodtsev, S.I.
Author_Institution :
Moscow State Univ., Russia
fDate :
6/1/1995 12:00:00 AM
Abstract :
Optical reflectance spectra of thin YBCO films on SrTiO/sub 3/ bicrystals were measured in a photon energy range of 1-3 eV at room temperature. Raman spectra measurements in the range 200-700 cm/sup -1/ were performed. The best samples were shown to have high reflectance anisotropy and a well-defined Raman peak /spl nu//sub 1/=500+1 cm/sup -1/. YBCO thin films on a bicrystal substrate that successfully passed optical control were used for Josephson junctions and DC SQUID fabrication. The fabricated SQUIDs operated at 77.3 K in the flux locked loop mode and had a typical white noise (1-2)/spl times/10/sup -5/ /spl Phi//sub 0//Hz/sup 1/2/ at frequencies higher than 200-500 Hz. The best magnetic field resolution was 650 fT/Hz/sup 1/2/ at frequencies f>200 Hz.<>
Keywords :
Josephson effect; Raman spectra; SQUIDs; barium compounds; high-temperature superconductors; infrared spectra; reflectivity; superconducting device noise; superconducting device testing; superconducting thin films; visible spectra; white noise; yttrium compounds; 1 to 3 eV; 200 to 500 Hz; 200 to 700 cm/sup -1/; 77.3 K; DC SQUID fabrication; Josephson junctions; Raman spectra; SrTiO/sub 3/; SrTiO/sub 3/ bicrystal substrate; YBCO thin film DC SQUIDs; YBa/sub 2/Cu/sub 3/O/sub 7/; flux locked loop mode; high reflectance anisotropy; magnetic field resolution; optical control; optical diagnostics; optical reflectance spectra; photon energy range; room temperature; white noise; Energy measurement; Frequency; Optical device fabrication; Optical films; Performance evaluation; Reflectivity; SQUIDs; Temperature distribution; Temperature measurement; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
