Measurement of the size dependence of the current-phase relation in microbridge Josephson junctions

Abstract
We present the first direct measurements of the size effect on the current‐phase relation of microbridge Josephson junctions. The phase difference across the bridge is obtained by subtracting the phase shift of the thin‐film leads from the total phase shift. We have found that the current‐phase relations are sinusoidal for both uniform and variable thickness bridges with dimensions much smaller than ξ (T). For narrow uniform thickness bridges with width ≪ξ (T), the measured length dependence of the current‐phase relation is in good agreement with the calculation of Likharev and Yakobson for variable thicknes bridges.