US 4,176,290 AGranted

Superconductive Josephson circuit device

AssigneeNippon Telegraph & Telephone Public Corporation

InventorsAkira Ishida, Hajime Yamada

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Abstract

A superconductive Josephson circuit device for shift register comprises at least three superconductive quantum interference closed loops magnetically connected to each other in series configuration. The superconductive quantum interference loops each include at least one Josephson junction, having a property of causing a magnetic flux to be quantized as a predetermined unit called "flux quantum". The Josephson junction free portions of one loop are arranged in proximity to the Josephson junction free portions of the other loop in a manner to obtain a desired magnetic coupling. Clock current feeding lines for feeding clock currents which bring magnetic flux into the superconductive quantum interference loops are provided to permit a flux quantum number in the loop to be controlled to a predetermined amount (0 or 1). A clock current control circuit controls the supply of the clock current and its timing to permit a flux quantum number "0" or "1" to be shifted as binary information from loop to loop.

Claims8

Dependent claims

A superconductive Josephson circuit device for use in a shift register, comprising:

at least three superconductive closed loops, each of said superconductive closed loops including at least one Josephson junction capable of carrying Josephson current I.sub.J and having a Josephson junction free portion including inductance L, wherein the inductance-Josephson current product, LI.sub.J, is selected around magnetic flux quantization unit, .PHI..sub.o =2.07.times.10.sup.-15 Webers, whereby trapping and releasing of a magnetic flux quantum are made therein, each closed loop having no resistive component of impedance;
coupling means for providing a predetermined amount of loop-to-loop coupling so that said superconductive closed loops are magnetically coupled with each other in series fashion such that said Josephson junction-free portion of each superconductive closed loop is located close to the Josephson junction free portion of at least two adjacent superconductive closed loops;
and
shift operation control means for providing a magnetic flux into each of said superconductive closed loops and for causing a magnetic flux quantum to be trapped into the loops or to be released from the loops, whereby a magnetic flux quantum representing a logic "1" data information is sequentially shifted from loop to loop in shift register fashion.

1 more element

Dependencies are inferred from the claim text.