SQUIDs employing microbridges of large cross-sectional areas have been constructed from granular superconducting Al-Al2O3 films. Films having high normal-state resistivities were used for their low values of critical current densities. Although the penetration depth in such films is large compared with their thickness, we find that the flux is still quantized in units of Φ0 and that the noise level is close to intrinsic as calculated by Jackel and Buhrman. It is only for very large values of the penetration depth (λ > 10Μm) that the signal-to-noise ratio is expected to deteriorate.
|Number of pages||15|
|Journal||Journal of Low Temperature Physics|
|State||Published - Sep 1978|