Asymmetric dc-SQUIDs: Magnetic and noise properties

SQUID configurations with an asymmetry in both the critical current and the normal resistance of the two Josephson junctions have been numerically analyzed. The analysis has been carried out on a high performance computer, by choosing parameters typical of low critical temperature SQUIDs. In particular the dependence of both the magnetic nux noise Sm and the flux to voltage transfer function Vm on the bins current and the normalized SQUID inductance Shave been investigated Thermal noise effects, including contributions of both junction and damping resistance, have been introduced in the calculations. The results show that an increase of the asymmetry leads to higher V-Phi and lower S-Phi,values. This suggests to use asymmetric dc-SQUIDs to improve the device performance for both small and large inductance values.