Sperry Corporation

Mark F Sweeny

David L Fleming

Meir Gershenson

Robert E Barta

Dennis D Long

A thin, nominally 150 angstroms, normal metal layer, nominally the noble normal metal palladium, sandwiched intermediate between two superconducting layers, nominally niobium, supports totally superconducting current flow therethrough such normal metal layer by the quantum mechanical tunneling effect. Such a thin normal metal layer is useful as a stop etch layer for fabrication process control, including especially the selective niobium anodization process, as an oxidation resistant or immune layer to which totally superconducting electrical contact may be reliably made such as by soldering, and as a patterned resistor in those regions of the substrate plane where such thin normal metal layer is not sandwiched by superconducting layers. Particularly concerning such stop etch function, a thin normal layer of palladium will serve as a stop etch layer to the etching of niobium while not precluding totally superconducting contact therethrough such thin palladium layer. Particularly concerning the electrical contact function, a superconducting wire, nominally niobium, may be soldered with lead-tin or indium-tin to a thin normal metal layer of palladium in the formation of a totally superconducting connection therethrough such thin palladium layer. Particularly concerning such patterned resistor, terminus superconducting sandwiches of niobium-thin palladium-niobium may be electrically resistively interconnected by such thin palladium layer precisely patterned in the region(s) wherein it is not sandwiched, only such unsandwiched region(s) of such thin palladium layer contributing controllably determinable resistance to the interconnection(s).

Intermediate normal metal layers in superconducting circuitry

A D.C. isolation transformer consisting of a primary group of one or more flux shuttles coupled, preferably inductively coupled but alternatively capacitively or resistively coupled, to a secondary group of one or more additional flux shuttles is capable of transforming, and transmitting, power at both alternating and direct currents. A flux shuttle is a plurality, n, of Josephson junctions interconnected in parallel one to the next by like plurality minus one, n-1, of inductors. When the Josephson junctions and the inductors are equivalent within and between the flux shuttles as comprise both the primary and the secondary of the transformer then the transformer device will have a voltage gain of exactly an integer number, i.e. 2, 3, 4 etc. The transformer is preferably implemented in planar thin film technology, the Josephson junctions being created with the Selective Non-Anodizing Process (SNAP) while the inductors are superconducting stripline.

Transformer built of coupled flux shuttles

A type of Superconducting Quantum Interference Device (SQUID) requires that relatively large, circular, toroidally wound wire coils within a first cavity of a superconducting canister should be inductively coupled to a relatively small SQUID created as an annular ring plus Josephson junctions upon a substrate within a second cavity of the superconducting canister. The required inductive coupling is through a dielectric filled cavity called a coupling cavity which is conical in the shape of a dunce's cap. The conically shaped coupling cavity within the superconducting canister minimizes the parasitic stray inductance which is coupled to the SQUID, and thusly improves the noise performance of the SQUID.

Growing community of inventors

Saint Paul, MN, United States of America

Mark F Sweeny