Title :
High-Tc thin-film magnetometer
Author :
Miklich, A.H. ; Wellstood, F.C. ; Kingston, J.J. ; Clarke, J. ; Colclough, M.S. ; Cardona, A.H. ; Bourne, L.C. ; Olson, W.L. ; Eddy, M.M.
Author_Institution :
Dept. of Phys., California Univ., Berkeley, CA, USA
fDate :
3/1/1991 12:00:00 AM
Abstract :
The authors have constructed and tested high-Tc magnetometers by coupling a high-T c thin-film superconducting quantum interference device (SQUID) to two different high-Tc thin-film flux transformers. The SQUID was made from Tl2CaBa2Cu 2O8+y films grown on MgO, with junctions consisting of native grain boundaries. The flux transformers were made from YBa2Cu3O7-x, and each had ten-turn input coils and a single-turn pickup loop. The first transformer, which was patterned with a combination of shadow masks and photolithography, yielded a magnetic field gain of about -7.5, functioned up to 79 K, and gave a magnetic field sensitivity BN (10 Hz)≈ 3.1 pT Hz-1/2 at 38 K. The second transformer, which was patterned entirely by photolithography, yielded a gain of about -8.7 functioned up to 25 K, and had a sensitivity BN (10 Hz)≈3.5 pT Hz-1/2 at 4.2 K. In both cases, the limiting noise arose in the SQUID
Keywords :
SQUIDs; barium compounds; calcium compounds; high-temperature superconductors; magnetometers; superconducting thin films; thallium compounds; yttrium compounds; 4.2 to 79 K; MgO; Tl2CaBa2Cu2O8+y-MgO; YBa2Cu3O7-x; flux transformers; high temperature superconductors; magnetic field gain; magnetic field sensitivity; native grain boundaries; Couplings; Interference; Lithography; Magnetic fields; SQUID magnetometers; Superconducting devices; Superconducting thin films; Testing; Thin film devices; Transformers;
Journal_Title :
Magnetics, IEEE Transactions on
