M. Kawasaki, P. Chaudhari, et al.
Physical Review Letters
We report on the characteristics of YBa2Cu307_δ grain boundary junction (GBJ) dc-SQUIDs with a square washer geometry design. The current-voltage characteristics of these SQUIDs are close to those predicted by the resistively shunted junction (RSJ) model. Their flux-voltage characteristics are perfectly periodic from 4.2 to 87K. The noise characteristics have been measured as a function of frequency, temperature, bias current, and applied magnetic flux. At frequencies above about 1kHz kHz the magnetic flux noise energy of the GBJ-SQUIDs is frequency independent and close to the theoretical value estimated from the Nyquist noise in the junction normal resistance. At lower frequencies the noise scales approximately as 1/f. Above about 82-85K the 1/f noise is dominated by flux noise presumably caused by thermally assisted flux motion in the film. Below this temperature it is dominated by voltage noise across the junctions. © 1991 IEEE
M. Kawasaki, P. Chaudhari, et al.
Physical Review Letters
L.R. Narasimhan, M. Takigawa, et al.
Applied Physics Letters
R.G. DeVoe, R. Kallenbach, et al.
QELS 1992
M. Kawasaki, E. Sarnelli, et al.
Applied Physics Letters