Abstract: The invention relates to a Josephson device and a method of manufacturing such a device which comprises two layers 11, 11' of an oxidic superconducting material between which at least one non-superconducting layer 13 of silver sulphate is provided. The non-superconducting layer 13 is connected to the superconducting layers 11, 11' through silver layers 12, 12'.

Abstract: A method of producing a Josephson junction device consisting of thin films of superconducting materials such as niobium and niobium nitride that work at cryogenic temperatures, in which a base electrode layer, tunnel barrier layer and a counterelectrode layer constituting a Josephson junction are formed on a substrate. In order to form a desired electrode pattern on the counterelectrode layer, a resist pattern is used as a mask for dry etching, followed by a plasma ashing process for ablating part of the resist in order to form a terrace-shaped portion at the edges and corners of the counterelectrode pattern by reforming and shrinking the cross-sectional geometry of the resist. Then, a thin insulating film for covering the edged layers is deposited over the entire surface of substrate, followed by the removal of said resist pattern together with said insulating film deposited on said resist pattern in order to form a protecting layer around the counterelectrode pattern.

Abstract: One or more monolayers of cerium arrayed on the surface of a niobium metal acts as a catalyst to oxidation of the niobium at ambient temperature and results in a very thin, very high quality insulating layer which may be configured by patterning of the catalyst. Significant amounts of Nb.sub.2 O.sub.5 are formed at pressures as low as 6.6.times.10.sup.-6 Pa, promoted by the presence of the cerium. This catalytic activity is related to the trivalent to tetravalent valence change of the cerium during oxidation. The kinetics of Nb.sub.2 O.sub.5 formation beneath the oxidized cerium shows two stages:the first stage is fast growth limited by ion diffusion;the second stage is slow growth limited by electron tunneling.Other catalytic rare earths usable instead of cerium are terbium and praseodymium; other substrate materials usable instead of niobium are aluminum, hafnium, silicon and tantalum, or oxidizable alloys thereof.