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Josephson Devices
Antonio Barone
Sergio Pagano
ABSTRACT In this chapter we briefly review the main applications of
Josephson effect together with the most essful devices realized. We will
give an overview of the various devices, providing also some basic concepts
of the underlying physical mechanisms involved, and the associated limit
performances. Some considerations on the concrete possibilities of ess-
ful “market ready” implementation will also be given.
1 Introduction
Some stimulating aspects of Josephson structures have been considered in
detail in other contributions to the present volume. In this reviewweshall
confine our attention to the main features of superconductive electronics
which, as far as the active devices is concerned, can be considered as entirely
based on the Josephson junctions.
We consider first the physical principles underlying the operation of such
devices in the various applications both potential or already realized.
It is quite usual to distinguish ponents in the two classes
of “analog” and “digital” devices. In both cases one can resort to general
properties of superconductivity and specific features of the Josephson effect.
Within these classes of devices the most stimulating aspects which make
the superconductive technology petitive are the possibility of en-
hancing processing speed of digital circuits and realizing ic field
sensors of extreme sensitivity. The former is based on the intrinsic speed
that Josephson junctions, in different configurations (latching mode, RSFQ
mode, etc.), can offer and, even more, the extremely lowpowerdissipation
involved. This last issue is further improved by the possibility of super-
conductive interconnection of microstrips which allows a sort of ballistic
transfer of pulses due to the very lowattenuation and dispersion.
As for the ic field sensors the petitiveness lies in
bination of fundamental properties of superconductivit