Browse Prior Art Database

Structure for High Temperature Josephson Bridges

IP.com Disclosure Number: IPCOM000108179D
Original Publication Date: 1992-Apr-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 38K

Publishing Venue

IBM

Related People

Kleinsasser, AW: AUTHOR

Abstract

Disclosed is a structure which allows the reliable fabrication of Josephson junctions based on high transition temperature superconductors.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 63% of the total text.

Structure for High Temperature Josephson Bridges

      Disclosed is a structure which allows the reliable fabrication
of Josephson junctions based on high transition temperature
superconductors.

      Reliable fabrication of a high temperature Josephson tunnel
junction would require the ability to form a stable barrier which is
only a few monolayers thick between two films which have good
superconducting properties to within a few monolayers of the
interface.  This ability has not been demonstrated to date. Weak link
structures, in which a small bridge connecting two superconducting
banks provides the weak coupling, are therefore attractive.  The
superconductor-normal-superconductor (SNS) structure is particularly
attractive because the properties of the bridge material can be
tailored to give the desired impedance and characteristic voltage.

      The structure of this invention consists of two
superconductor-normal bilayer films separated by a submicrometer gap,
with a narrow metal bridge connecting them.  The bilayer consists of
a high temperature superconductor (for example, YBCO) and a thin
layer of normal metal (eg. Au).  The distinguishing feature of this
invention is the use of a superconductor-normal bilayer as the basis
for the device.  The normal layer, which is much thinner than the
coherence length in the material, is deposited on the superconductor
before patterning, and protects it from degradation during device
processing. Ideally the norm...