Title :
DC SQUID magnetometers with the directly coupled pick-up loop
Author :
Keunseop Park ; Soon-Gul Lee ; Hyuk Chan Kwon ; Yong Ki Park ; Jong-Chul Park
Author_Institution :
Korea Res. Inst. of Stand. & Sci., Taejon, South Korea
fDate :
6/1/1995 12:00:00 AM
Abstract :
DC SQUID magnetometers with a directly coupled square pick-up loop have been made from single layer YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// thin films using step edge junctions or bicrystal grain boundary junctions on SrTiO/sub 3/ substrates. YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// thin films were deposited by off-axis RF sputtering or laser ablation and patterned by photolithography and Ar ion milling to form the SQUID, pick-up loop and modulation coil. The SQUIDs showed RSJ like current vs. voltage characteristics and voltage modulation in response to external fields at 77 K. The SQUID inductance was 55-140 pH, pick-up loop size was 47 mm/sup 2/ and the effective area of magnetometers estimated from the measured modulation period was 0.2-0.4 mm/sup 2/. The magnetic field noise was 7.4/spl times/10/sup -13/ T//spl radic/(Hz) at 10 Hz and 77 K.<>
Keywords :
SQUID magnetometers; barium compounds; high-temperature superconductors; superconducting thin films; yttrium compounds; 77 K; Ar; Ar ion milling; DC SQUID magnetometers; HTS film; HTSC; SrTiO/sub 3/; SrTiO/sub 3/ substrates; YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta//; YBa/sub 2/Cu/sub 3/O/sub 7/; bicrystal grain boundary junctions; directly coupled pick-up loop; laser ablation; modulation coil; offaxis RF sputtering; photolithography; single layer YBCO thin films; step edge junctions; Couplings; Grain boundaries; Laser ablation; Lithography; Magnetic field measurement; Magnetic modulators; Radio frequency; SQUID magnetometers; Sputtering; Voltage;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
