Conductus, Inc.

Gregory G Zaharchuk

Nathan Newman

Kookrin Char

Stephen M Garrison

A novel method of producing weak-link grain boundary Josephson junctions in high temperature superconducting thin films is disclosed. These junctions are reliably and reproducibly formed on uniform planar substrates (10) by the action of a seed layer (40) placed intermediate the substrate (10) and the superconductor film (20). The superconductor film (22) grown atop the seed (42) is misoriented from the rest of the film (24) by an angle between 5.degree. and 90.degree.. The grain boundary (30) so formed acts as a high quality weak-link junction for superconductor devices. The performance of these junctions can be improved by the addition of buffer layers (50, 60) between the substrate (10) and the superconductor film (20).

Method of forming grain boundary junctions in high temperature

Grain boundary, weak-link junctions are formed at a predermined location of a uniform, planar substrate by depositing superconducting film on two sections of the substrate. The film is grown as a bicrystal having two distinct areas of superconducting film whose crystal lattices are rotated with respect to each other, either in-plane or out-of-plane, by more than 5.degree. and less than 90.degree.. The grain boundary acts as a weak link junction. The film can be induced to grow as a bicrystal by depositing intermediate strata such as seed layers or buffer layers or by modifying the growth conditions during deposition.

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Palo Alto, CA, United States of America

Gregory G Zaharchuk