Title :
Relaxation-oscillation-driven DC SQUIDs
Author :
Gudoshnikov, S.A. ; Maslennikov, Yu.V. ; Semenov, V.K. ; Snigirev, O.V. ; Vasiliev, A.V.
Author_Institution :
Dept. of Phys., Moscow State Univ., USSR
fDate :
3/1/1989 12:00:00 AM
Abstract :
Simple and reliable relaxation-oscillation (RO)-driven DC SQUIDs (superconducting quantum interference devices) have been fabricated with a flux-to-voltage factor H up to 1 mV/Φ0 and internal energy sensitivity Ev of (4±1) × 10-31 J/Hz at frequencies above 10 Hz and 1×10 -29 (1 Hz/f) J/Hz at lower frequencies. Supplied with a 50-μm-wire 20-turn spiral input coil and a 6-cm2 pickup loop, such SQUIDs provided magnetic field sensitivity close to (6±3)×10-15 T/Hz1/2 above 10 Hz. The dynamic range of the magnetometers was close to 1.5×107 Hz1/2 above 10 Hz. The maximum slew rate was about 10 μT/s at 0.1 kHz. Successful records of Earth-ionosphere magnetic resonances have been obtained with these magnetometers housed in a stainless steel transport dewar. A balanced version of the RO-driven DC SQUID is suggested with improved H and Ev
Keywords :
SQUIDs; magnetometers; DC SQUIDs; Earth-ionosphere magnetic resonances; flux-to-voltage factor; internal energy sensitivity; magnetic field sensitivity; magnetometers; pickup loop; relaxation oscillation driven; slew rate; spiral input coil; stainless steel transport dewar; Coils; Dynamic range; Frequency; Interference; Magnetic fields; Magnetic resonance; SQUID magnetometers; Spirals; Superconducting devices; Superconducting magnets;
Journal_Title :
Magnetics, IEEE Transactions on
