Title :
Investigation of thin film DC SQUID gradiometer using a single YBCO layer
Author :
Seidel, P. ; Zakosarenko, V. ; Schmidl, F. ; Dorrer, L. ; Schneidewind, H. ; Linzen, S. ; Il´ichev, E.V. ; Darula, M.
Author_Institution :
Inst. fur Festkorperphys., Friedrich-Schiller-Univ., Jena, Germany
fDate :
6/1/1995 12:00:00 AM
Abstract :
Thin film DC SQUID gradiometers with a large effective pickup area using only a single YBa/sub 2/Cu/sub 3/O/sub 7-x/ layer and step edge Josephson junctions on SrTiO/sub 3/ substrate have been prepared. The planar gradiometer consist of two loops coupled directly to a small area SQUID in the center of the structure. The main advantage in comparison to magnetometers is the possibility of direct measurements in magnetically unshielded environment. At 77 K without bias reversal technique we obtain a white noise level about 3.6/spl times/10/sup -5/ /spl Phi//sub 0//Hz/sup 1/2/ or 700 fT/cmHz/sup 1/2/. Some peculiarities for a two SQUID arrangement with 4 Josephson junctions are observed and simulated on the base of the RSJ model.<>
Keywords :
Josephson effect; SQUID magnetometers; barium compounds; high-temperature superconductors; superconducting device noise; superconducting thin films; white noise; yttrium compounds; 77 K; RSJ model; SrTiO/sub 3/; SrTiO/sub 3/ substrate; YBa/sub 2/Cu/sub 3/O/sub 7-x/ layer; YBaCuO-SrTiO/sub 3/; direct measurements; large effective pickup area; magnetically unshielded environment; single YBCO layer; step edge Josephson junctions; thin film DC SQUID gradiometer; two SQUID arrangement; white noise level; High temperature superconductors; Josephson junctions; Laser ablation; Magnetic field measurement; SQUID magnetometers; Sputtering; Substrates; Superconducting thin films; Transistors; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
