Operation of Low-$T_{c}$ Circuits in a Magnetic Environment

Low-T
_c
rapid single flux quantum (RSFQ) digital circuits without magnetic shielding fabricated with the FLUXONICS Foundry have been studied in the presence of external magnetic fields. Magnetic fields parallel to the plane of the chip are shown to influence more drastically the nominal behavior of the circuits above 5 μT, while perpendicular magnetic fields can reach 15 μT without affecting significantly their operation. This is confirmed by experimental SQUID interference patterns.