J. Ramos et al., KEY COMPONENTS FOR THE FABRICATION OF YBA2CU3O7-DELTA FLIP-CHIP SQUIDMAGNETOMETERS AND CURRENT SENSORS, Superconductor science and technology, 11(9), 1998, pp. 887-890
We have prepared single layer washer-type de superconducting quantum i
nterference devices (SQUIDs), multilayer flux transformers and input c
oils as key components for flip-chip SQUID magnetometers and current s
ensors. The do SQUIDs are prepared on a SrTiO3 bicrystal substrate wit
h a misorientation angle of 30 degrees. The maximum peak-to-peak flux
modulated voltage amounts to typically 40-60 mu V for a SQUID inductan
ce of 80 pH. YBa2Cu3O7-delta flux transformers and input coils are pre
pared on a SrTiO3 single crystal polished on both sides with dimension
s 10 mm x 10 mm x 1 mm. The preparation process of these structures in
volves the deposition of YBa2Cu3O7-delta and SrTiO3 layers by pulsed l
aser ablation and pattern definition by dry etching. The flip-chip mag
netometers with 80 pH SQUIDs provide a field sensitivity equal to 2.6
nT Phi(0)(-1) whereas current sensors show a sensitivity equal to 2.6
mu A Phi(0)(-1). The best value for the magnetic field resolution is 2
0 fT Hz(-1/2) in the white noise region and 100 fT Hz(-1/2) at 1 Hz wi
th a 1/f corner at 10 Hz. Current resolution values are typically 40 p
A Hz(-1/2) in the white noise region.