Title :
Monolithic flux transformer-coupled high-T/sub c/ DC SQUID magnetometers
Author :
Hilgenkamp, J.W.M. ; Brons, G.C.S. ; Hoogeveen, S. ; Flokstra, J. ; Rogalla, H.
Author_Institution :
Dept. of Appl. Phys., Twente Univ., Enschede, Netherlands
fDate :
6/1/1995 12:00:00 AM
Abstract :
YBa/sub 2/Cu/sub 3/O/sub 7-x/ based monolithic flux transformer-coupled high-T/sub c/ DC SQUID magnetometers operating up to 73 K have been realized. The devices are characterized by high values of the modulation voltage, up to 32 /spl mu/V at 40 K. A minimal white noise level of 0.10 pT//spl radic/Hz was obtained above 200 Hz, and 0.64 pT//spl radic/Hz at 1 Hz and 55 K. The temperature dependence of the modulation voltage, the effective sensing area and the field sensitivity are discussed. Model-calculations have been performed to investigate high frequency resonances in the washer-input coil structure. Methods for damping are considered.<>
Keywords :
SQUID magnetometers; barium compounds; high-temperature superconductors; modulation; resonance; superconducting device noise; white noise; yttrium compounds; 40 to 73 K; DC SQUID magnetometers; HTS device; HTSC magnetometer; YBa/sub 2/Cu/sub 3/O/sub 7/; damping methods; effective sensing area; field sensitivity; high frequency resonances; high-T/sub c/ magnetometers; model calculations; modulation voltage; monolithic flux transformer-coupled magnetometer; temperature dependence; washer-input coil structure; white noise level; Coils; Couplings; Damping; Electric variables; Fabrication; Grain boundaries; Resonant frequency; SQUID magnetometers; Temperature dependence; Voltage;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
