Browse Prior Art Database

Filament Josephson Devices

IP.com Disclosure Number: IPCOM000081844D
Original Publication Date: 1974-Aug-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Laibowitz, RB: AUTHOR

Abstract

The disclosed Josephson-device structures are small, dense, rugged and inexpensive to fabricate.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 84% of the total text.

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Filament Josephson Devices

The disclosed Josephson-device structures are small, dense, rugged and inexpensive to fabricate.

A technique has been described for forming conductive paths, i.e., metallic filaments in an insulating or semiconducting thin-film material. The insulating film is sandwiched between two metallic conductors either in a multilevel or in a planar array.

The electrode-separation dimension of the basic geometry is a few tenths of a micron which sets the upper limit for the filament length; however, lengths up to a few microns can also be used. The thickness or diameter of the filament may be much less. Although the geometry of the filaments may be quite irregular, they are assumed to be cylindrical herein. Thus, the length and diameter of the filament may be made < the coherence length of the particular superconducting material involved which is generally on the order of a few tenths of a micron. Alternatively, the larger filaments (up to a few microns) can be used for those materials in which the penetration depth is the critical length. Filaments of these sizes exhibit Josephson effects and become Josephson weak links.

The actual formation of the filaments consists of two breakdown or forming steps or two discretionary writing steps. A loop is constructed in which two weak links are established with an enclosed area; the ends of the links are connected via the existing electrodes. This loop can be operated as a magnetometer. Such magnetometers...