Browse Prior Art Database

Josephson Devices Using Amorphous Superconductors

IP.com Disclosure Number: IPCOM000084917D
Original Publication Date: 1976-Jan-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Chaudhari, P: AUTHOR [+2]

Abstract

A Josephson tunneling device is a superconductive device having two electrodes between which is a tunnel barrier. This tunnel barrier is generally a reactive layer, such as an oxide, of the base electrode. Its thickness is typically 2-60 angstroms.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 79% of the total text.

Page 1 of 1

Josephson Devices Using Amorphous Superconductors

A Josephson tunneling device is a superconductive device having two electrodes between which is a tunnel barrier. This tunnel barrier is generally a reactive layer, such as an oxide, of the base electrode. Its thickness is typically 2-60 angstroms.

It is proposed to use amorphous superconductors as electrodes in a Josephson tunneling device, where the tunnel barriers are conveniently oxides of the base electrode. Examples of suitable amorphous superconductors are Be, Pb-Bi, Pb-Hg, Nb-Ge, Nb-Al, La-Al, La-Ni, Nb-Sn, Mo-Zr, and Mo-Ru.

These amorphous materials are superconducting at temperatures between 3 degrees K and 11 degrees K. They can be prepared by coevaporation at low temperatures (4.2 degrees K or 77 degrees K) or by cosputtering at low temperatures. Additionally, they can be prepared by liquid quenching of a molten solution of the constituent elements (splat cooling) to a low-temperature substrate (for instance a substrate at 77 degrees K). The superconducting amorphous material is oxidized in conventional ways to provide the tunnel barrier, after which the second amorphous electrode is formed in the same manner.

Josephson tunneling devices made from amorphous superconductors and their oxides have several advantages, including mechanical stability which is superior to that of Josephson tunneling devices made from crystalline materials. Also, the amorphous superconducting films will be homogeneous and isot...