Abstract: Methods and apparatus are disclosed for operating a memory cell formed from the plurality of coupled Josephson junctions. The memory cell is configured such that applying an electrical signal to the junctions can cause at least one, but not all, of the junctions to change their respective phase states. Subsequent writes to the memory cell using substantially the same electrical pulse do not change the phase state of the plurality of junctions. The memory cell can be ready by providing another electrical pulse to one of the junctions and receiving an output electrical pulse generated in response by a different Josephson junction of the memory cell. A set of phase states are selected to represent the logic values that are stable across anticipated operating conditions for the memory cell. Methods of selecting electrical parameters and manufacturing memory cells are further disclosed.

Abstract: One embodiment describes a memory cell. The memory cell includes a phase hysteretic magnetic Josephson junction (PHMJJ) that is configured to store one of a first binary logic state corresponding to a binary logic-1 state and a second binary logic state corresponding to a binary logic-0 state in response to a write current and to generate a superconducting phase based on the stored digital state. The memory cell also includes at least one Josephson junction having a critical current that is based on the superconducting phase of the PHMJJ and being configured to provide an output corresponding to the stored digital state in response to a read current.

Abstract: A superconducting memory cell includes a magnetic Josephson junction (MJJ) with a ferromagnetic material, having at least two switchable states of magnetization. The binary state of the MJJ manifests itself as a pulse appearing, or not appearing, on the output. A superconducting memory includes an array of memory cells. Each memory cell includes a comparator with at least one MJJ. Selected X and Y-directional write lines in their combination are capable of switching the magnetization of the MJJ. A superconducting device includes a first and a second junction in a stacked configuration. The first junction has an insulating layer barrier, and the second junction has an insulating layer sandwiched in-between two ferromagnetic layers as barrier. An electrical signal inputted across the first junction is amplified across the second junction.

Abstract: A magnetic memory system includes a superconductor circuit and one or more magnetic memory elements to store data. To write data, a driver circuit in the superconductor circuit generates a magnetic signal for transmission over a superconductor link extending between the superconductor circuit and the magnetic memory element. To read data, a sensing circuit in the superconductor circuit monitors a superconductor link extending from sensing circuit to the magnetic memory element. The magnetic memory element can be a spin-transfer type magnetic memory element.

Abstract: A superconducting memory cell includes a magnetic Josephson junction (MJJ) with a ferromagnetic material, having at least two switchable states of magnetization. The binary state of the MJJ manifests itself as a pulse appearing, or not appearing, on the output. A superconducting memory includes an array of memory cells. Each memory cell includes a comparator with at least one MJJ. Selected X and Y-directional write lines in their combination are capable of switching the magnetization of the MJJ. A superconducting device includes a first and a second junction in a stacked configuration. The first junction has an insulating layer barrier, and the second junction has an insulating layer sandwiched in-between two ferromagnetic layers as barrier. An electrical signal inputted across the first junction is amplified across the second junction.

Abstract: In one embodiment, the invention is a hybrid superconducting-magnetic memory cell and array. One embodiment of a memory cell includes a magnetoresistive element and at least one superconducting element wired in parallel with the magnetoresistive element. In a further embodiment, memory cells of the disclosed configuration are arranged to form a memory array.

Abstract: Copper alloy foils are provided having far greater strength and heat resistance than conventional copper foils, and having better productivity, are characterized by a composition comprising, all by weight, from 0.01 to 0.4% Cr, from 0.01 to 0.25% Zr, from 0.02 to 2.0% Zn; and when necessary from 0.05 to 1.8% Fe and from 0.05 to 0.8% Ti; and when further necessary one or more elements selected from the group consisting of Ni, Sn, In, Mn, P, Mg, Al, B, As, Cd, Co, Te, Ag, and Hf in a total amount of from 0.005 to 1.5%; the balance being copper and unavoidable impurities. Inclusions in the copper foil not larger than 10 .mu.m in size, and the inclusions between 0.5 and 10 .mu.m in size number less than 100 pieces/mm.sup.2.

Abstract: A magnetic head has a superconducting quantum interference device having a ring made of a superconductive material including a Josephson junction which links to a magnetic flux generated by a magnetic recording medium, and a magnetic pole for guiding the magnetic flux generated by the magnetic recording medium or the ring made of a superconductive material arranged in parallel to a plane of the magnetic recording medium so that the magnetic flux generated by the magnetic recording medium flows into a through-hole of the ring. A magnetic recording and reproducing apparatus includes such a magnetic head, a winding to which a reproduced signal from the magnetic head is applied and the superconductive ring including the Josephson junction arranged such that the magnetic flux generated by the winding flows thereto.

Abstract: A composite includes granules of Type II superconducting material and granules of rare-earth permanent magnets that are distributed in a binder. The composite is a two-phase structure that combines the properties of the superconductor and magnets with the flexibility and toughness of a polymeric material. A bearing made from this composite has the load capacity and stiffness of a permanent magnet bearing with added stability from a Type II superconducting material.

Abstract: Read/write heads for exchanging information with a magnetic media in either vertical or horizontal recording modes include SQUID detectors coupled to the magnetic flux path of the head. Selective use of superconducting material improves the data interchange operating efficiency of the read/write head and its coils. Magnetic paths associated with head elements are confined and directed by superconducting material to produce compact data with minimal power requirements. Magnetic read/write heads containing Josephson junction or SQUID detectors and which are encased in superconductive material allow high density data recording and highly sensitive data detecting. Data density is also improved by selected application of superconductive material to magnetic read/write heads constructed for perpendicular recording.