TRIMMING METHOD FOR SQUID

PROBLEM TO BE SOLVED: To trim a shunt resistor without having any effect on the characteristics of a Josephson junction(JJ) while suppressing hysteresis by annealing the shunt resistor at a temperature which does not cause variation in the critical current of the JJ. SOLUTION: Each of a pair of Josephson junctions(JJ) 1 is connected in series with an inductor 2 having inductance equal to one half that of a superconducting quantum interference element and the two series circuits are connected in parallel. Each JJ 1 is connected with a parallel shunt resistor 3 and a damping resistor 4 is connected across the shunt resistor 3. The shunt resistor 3 is subjected to annealing and variation in the resistance Rs thereof is measured. The resistance Rs decreases as the annealing time increased. Consequently, the resistance Rs of the shunt resistor 3, decreased through annealing, is stabilized and the variation of resistance caused by the subsequent temperature rise is suppressed.