Northrop Grumman Systems Corporation

Microsoft Technology Licensing, LLC

Eric C Gingrich

Donald Lynn Miller

Randall M Burnett

Thomas F Ambrose

Timothy Richard Barbour

Ian M Dayton

Kurt Edward Dietrich

A bistable device allows supercurrent to flow when functioning in one regime, wherein magnetization directions of different magnetic layers are antiparallel, but restricts supercurrent when switched to function in a resistive regime, wherein the magnetization directions are parallel. In the first regime, the device acts as a Josephson junction, which allows it to be used in superconducting quantum interference devices (SQUIDs) and other circuits in which quantization of magnetic flux in a superconducting loop is desired. In the second, resistive regime, flux quantization is effectively eliminated in loops containing the device, and current is diverted to parallel superconducting components. The bistable device thereby acts as a superconducting switch, useful for a variety of circuit applications, including to steer current for memory or logic circuits, adjust logical circuit functionality at runtime, or to burn off stray flux during cooldown.

Superconducting switch

A sealed container having gloves attached thereto is provided as part of a physical properties measuring system (PPMS). The PPMS includes a sealed pressurized portion that is pressurized with a gas to purge out air from inside the sealed pressurized portion to reduce water vapor inside the sealed pressurized portion below a water vapor threshold. The system further includes a cryogenic tank having a cryostat disposed therein. The cryogenic tank contains a cryogenic liquid cooled to a cryogenic temperature. Test samples are placed inside the sealed pressurized portion in preparation of measuring physical properties of the test samples. One of the test samples is immersed in the cryogenic liquid to measure the physical properties. The test sample is removed from the cryogenic liquid and is exchanged for another test sample inside the sealed pressurized portion to prevent ice formation inside the cryostat.

Physical properties measurement system

Superconducting switch having a persistent and a non-persistent state and its use as a driver in a memory system are described. An example superconducting switch includes a first superconducting layer and a second superconducting layer. The superconducting switch includes a first magnetic layer having a fixed magnetization state. The superconducting switch includes a second magnetic layer capable of being at least in a first or a second magnetization state. The superconducting switch is capable of being in a first state or a second state, and the superconducting switch is configured such that an application of a magnetic field to the second magnetic layer changes a magnetization of the second magnetic layer from the first magnetization state to the second magnetization state placing the superconducting switch in the second state and a removal of the magnetic field automatically returns the superconducting switch from the second state to the first state.

Superconducting switch having a persistent and a non-persistent state

A milliohm resistor is fabricated as a Josephson junction device that contains ferromagnetic or antiferromagnetic material of sufficient thickness to render the device entirely resistive between terminals. The device can have a resistance on the order of milliohms and can be consume a much smaller chip footprint than resistors of the same resistance fabricated using conventional resistive materials. Because the device can be fabricated without modification to processes used to fabricate reciprocal quantum logic (RQL) circuitry, it can easily be incorporated in RQL circuits to mitigate flux trapping or to perform other functions where very small resistances are needed. In particular, the device can burn off circulating currents induced by trapped flux without affecting the transmission of SFQ pulses through RQL circuitry.

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Elkridge, MD, United States of America

Eric C Gingrich