Switching speed of DCL-gates with high-JcJosephson junctions

Switching speed and bias current margin of DCL-gates composed of high-Jcjunctions are investigated by both numerical calculation and experimental measurement. It is shown that switching speed is improved by increasing Jc. However, the switching speed and bias current margin of DCL-gates are restricted by the increase in the minimum resetting current for the high-Jcjunction. The theoretical Jclimit for a Nb oxide barrier junction is found to be about 7 × 10⁸A/m²from numerical results, and the Jcvalues that produce bias current margins of greater than 20 % are found by both numerical and experimental results to be less than A/m². The switching delay obtained experimentally for a DCL-gate with a Jcvalue of A/m²is 5.6 ps, which is in good agreement with the numerical result.