Circulating Current Ratio for DC SQUIDs

The circulating current in one Josephson junction of a DC SQUID is in the direction of translation current while in the other Josephson junction is in the opposite direction. Therefore, one interesting function is the circulating current ratio (CCR) which we define as: CCR = ( dissipative translation current 1 − circulating current )/( dissipative translation current 2 + circulating current ). We discuss the circulating current ratio in the loop of DC SQUIDs by considering the 20 on-chip high T C DC SQUIDs that Novikov et al. measured their transfer functions and flux shifts and reported in I.L. Novikov et al. (Physica C 469:30, 2009 ). A comparison between the CCR characteristics of those SQUIDs may be helpful in understanding the voltage-current and voltage-flux characteristics of asymmetric high T C DC SQUIDs.