| 摘要 |
PURPOSE:To enable a critical current value of a junction to be controlled as required during the operation of a device, by providing a control means for equalizing the critical current values of two tunnel-type Josephson junctions. CONSTITUTION:A direct-current superconducting quantum interference device (DC-SQUID) comprises, in addition to components identical with those of a conventional device, a main coil 1, a modulation coil 7 provided on the main coil 1 with electrical isolation therefrom, an insulation layer 2, a Josephson junction 3, an insulation layer 8 covering an upper electrode 4 and a shunt resistance 5, and control lines 9 provided over the tunnel-type Josephson junctions 3. Control current IC1 and IC2 is supplied to right-hand and left-hand control lines 9 so that the critical current values 1o of the right-hand and left- hand tunnel-type Josephson junctions 3 are controlled by means of magnetic fields produced by the control current IC1 and IC2. In this manner, the right-hand and left-hand critical current values Io can be equalized. |
