Although most superconducting circuits employed for small-scale applications use Josephson conjunctions as an active or switching element, in some important instances Josephson junctions should be replaceable by simple thin wires whose dimensions are of the size of the temperature-dependent coherence length, E(T). The researchers are studying theoretically the feasibility of a microcircuit which may behave in many respects like a SQUID (superconducting quantum interference device) circuit without the use of Josephson junctions. This device may be fabricated by means of a superconducting loop whose diameter is of the order of magnitude of the coherence length and has connected to it on opposite sides superconducting wires for the purpose of injecting an external control current. Magnetic flux B is applied perpendicular to the ring. The flux density gives rise to a circulating current. The circulating current density will be studied as a function of magnetic flux for various injected control currents, and these results will be extended to more complicated circuits such as finite and infinite ladder circuits and arrays.
