Accurate Determination of2ehin Y-Ba-Cu-O Josephson Junctions

Abstract

Accurate measurements of $\frac{2e}{h}$ by means of the ac Josephson effect have been carried out by the use of weak links of a high-$T_c$ superconductor, Y-Ba-Cu-O, of macroscopic dimensions. The result, $\frac{2e}{h}=483595.0\mathrm{}\pm 1.7$ GHz/V, differs, in relative value, from that obtained by accurate measurements in metallic superconductors by 5.6 × ${10}^{-6\mathrm{}}$.