Re. Miller et al., NIOBIUM TRILAYER JOSEPHSON TUNNEL-JUNCTIONS WITH ULTRAHIGH CRITICAL-CURRENT DENSITIES, Applied physics letters, 63(10), 1993, pp. 1423-1425
We describe the fabrication and properties of Nb-AlO(x)-Nb Josephson t
unnel junctions having critical current densities as high as 400 kA/cm
2, roughly an order of magnitude larger than any previously reported f
or this materials system. The quality of the junction characteristics,
as indicated by the current level at subgap voltages, is considerably
lower in high-J(c) than in low-J(c) junctions. However, over the enti
re high-J(c) range of 20-400 kA/CM2, the quality of our junctions rema
ins the same (i.e., subgap current scales with critical current).