At&t Bell Laboratories

Bell Telephone Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

Lucent Technologies Inc.

Other

American Telephone and Telegraph, Co.

At&t Technologies, Inc.

At&t Laboratories, Limited

Richard C Sherwood

Sungho Jin

Thomas H Tiefel

John J Mottine, Jr

Robert Bruce Van Dover

Gilbert Y Chin

Jack H Wernick

Ernst M Gyorgy

Lloyd Shepherd

Martin L Green

Chester M Bordelon

Joe A Fulton

Mark S Dentini

William C Vesperman

Murray Robbins

Harry John Leamy

Eva Milar Vogel

Robert L Billings

William R Lambert

Robert Zappulla

Stephen G Seger, Jr

Ho Sou Chen

Ho-Sou Chen

William J Tabor

Robert C Moore

Robert L Opila, Jr

Chester M Boredelon

Some mechanical, electrical, and thermal properties of high T,superconductors such as (Ba, Y) cuprates can be substantially improved by the dispersal of an appropriate metal in the superconductive body. For instance, mixing Ag particles with superconductive powder of nominal composition Ba,YCu,O,and processing the mixture in the conventional manner can produce superconductive bodies having T,of about 93 K and substantially greater fracture strength and normal state electrical and thermal conductivity than otherwise identical bodies that do not contain Ag particles.

Method of making a superconductive oxide body

Articles according to the invention comprise a superconductive cuprate (e.g., YBa.sub.2 Cu.sub.3 O.sub.7) body containing elongate grains measuring at least about 10 .mu.m along the long axis and having an aspect ratio of at least 10:1. Bodies according to the invention can have relatively high critical current density, as compared to analogous non-textured bodies.

Article comprising textured superconductive cuprate material

Articles comprising a quantity of superconductive oxide material can be fabricated by a process that comprises melting of part of an oxide precursor material, with resultant directional resolidification. Exemplary embodiments comprise zone melting and movement of the hot zone through the precursor material. The method can result in superconductive material having improved properties, e.g., higher critical current, as compared to prior art oxide superconductors.

Method of fabricating a superconductive body

Disclosed are normal metal-clad superconductive bodies (e.g., wires, ribbons) having a normal metal cladding that is porous during at least a part of the manufacture of the body. The porous cladding permits access of an ambient atmosphere to the superconductive material. Exemplarily, the superconductive material is an oxide such as a (Ba, Y) cuprate, the normal metal cladding comprises Ag particles (or Ag-coated particles), and the body is treated in an oxygen-containing atmosphere. Techniques for producing such a body are also disclosed.

Method of producing a superconductive body, and apparatus and systems

Electrical interconnections are made by means of a layer or sheet medium comprising chains of magnetically aligned, electrically conducting particles in a nonconducting matrix material. End particles of chains protrude from a surface of the medium, thereby enhancing electrical contact properties of the medium. The medium can be used for temporary as well as permanent connections; in the latter case the use of a nonconductive adhesive material is convenient for physical attachment to contacts on both sides of the medium.

Electrical interconnection by a composite medium

Superconductive oxide bodies such as wires, ribbons, rods, and other bulk bodies can be fabricated by a process that comprises melting precursor material, cooling at least of the melt such that a solid body of a desired shape results, and heat treating the solid body in an oxygen-containing atmosphere. The precursor material exemplarily is in the form of pressed superconductive oxide powder. The re-solidified superconductive material is relatively dense, typically textured, with relatively large grain size, and has improved properties, e.g., higher critical current density. An exemplary technique for melting of the precursor material is zone melting.

Fabrication of oxide superconductors by melt growth method

A compressible thermally conductive member comprises a polymer field with thermally conducting-magnetically aligned particles comprising a base portion and a multiplicity of protrusions extending from at least one surface of the base portion.

Thermal conductor assembly method

A method of producing normal-metal-clad superconductive oxide wire, tape and the like is disclosed. The method comprises forming an intermediate body by surrounding a quantity of the oxide powder (e.g., Ba.sub.2 YCu.sub.3 O.sub.6.9) with an appropriate normal metal jacket, reducing the cross section of the intermediate body by any appropriate technique (e.g., drawing or rolling), and heat treating the elongated body such that substantial sintering of the powder results, and such that, after completion of the heat treatment, the sintered oxide has a composition that is associated with superconductivity in unclad bulk samples of the oxide. The latter condition requires that at least the portion of the cladding that is in contact with the oxide powder is substantially inert with respect to oxygen and the oxide under the conditions of the heat treatment. Silver is the currently preferred inert normal metal. Exemplarily, Ag can be used to provide a diffusion barrier with other normal metal (e.g., Ni and Cu) surrounding the diffusion barrier, or the cladding can consist substantially of Ag. Various techniques for preventing oxygen loss and/or restoring lost oxygen from the powder are disclosed. Advantageously the elongated body is appropriately shaped (e.g., wound into a helical coil) prior to the heat treatment. Elongate bodies produced according to the invention can advantageously be used as superconductive magnets, and in a variety of other apparatus and systems.

Apparatus and systems comprising a clad superconductive oxide body, and

An electrical interconnection medium is made as a composite of electrically conducting, magnetic particles in a nonconductive matrix material. Particles are magnetically aligned into a network which extends in at least two dimensions as, e.g., in a sheet or layer medium. A layer medium may further include additional, larger conductive particles which may be magnetically aligned into columns extending the thickness of the medium; typically, in this case, the medium serves as an anisotropically conductive medium in the direction of the columns, with slight in-plane conductivity imparted by the network aiding the dissipation of electrostatic charge.

Composite electrical interconnection medium comprising a conductive

A compressible thermally conductive member comprises a polymer field with thermally conducting magnetically aligned particles comprising a base portion and a multiplicity of protrusions extending from at least one surface of the base portion.

Thermal conductor assembly

Devices such as, e.g., switches, flowmeters, and proximity sensors, as well as implant devices are made comprising an elongated ferromagnetic element. When the element is exposed to a variable magnetic field an electrical signal is obtained between contact points of the element in response to a change in the magnetic field. Preferred elongated elements have a helically deformed microduplex structure as may be produced by heat treatment and plastic twisting of a body of an alloy such as, e.g., an iron-nickel alloy.

Magneto-electric sensor device and sensing method using a sensor element

Electrical interconnection is established by means of an anisotropically conductive, composite layer medium comprising electrically conductive particles in a nonconductive matrix material. Enhanced uniformity of conductivity across the medium, and minimized incidence of lateral shorting are achieved as a result of essentially uniform distribution of electrically conductive particles which are also magnetic, such distribution resulting upon application of a magnetic field essentially perpendicular to a layer before or during hardening of the matrix material.

Anisotropically conductive composite medium

Electrical signals are produced by a pressure-responsive device, such signals being indicative of the position of locally applied pressure. The device comprises a position sensor assembly which comprises a composite layer medium including electrically conductive magnetic particles in a nonconductive matrix material. The particles are aligned into chains extending across the thickness of the layer, and chains include a non-conductive gap which is bridged upon application of sufficient pressure. The medium is sandwiched between sheet electrodes, and the resulting assembly may be transparent as is advantageous in writing pad and touch-sensitive screen applications. The pressure-responsive device is suitable, e.g., as an input device in graphics information systems, in combination with transmission and display facilities.

Pressure-responsive position sensor

Wide temperature range magnetic bubble memories are realized by using new compositions of rare earth garnets which require nonlinear bias field for operation over a given temperature range. The bias field structure for providing the corresponding nonlinear bias field includes plates of barium ferrite plus additional plates of Ni-Cu alloys and/or polycrystalline dysprosium (or other rare earths, singly or in combination) iron garnet to provide a nonlinear bias field versus temperature characteristic to match that of the bubble layer.

Bias magnet temperature tracking of magnetic bubble memories

Disclosed are magnetically soft ferritic multiphase Fe-Cr-Ni alloys containing at least about 82 weight percent Fe, between about 3 and about 10 weight percent Cr, and between about 2 and about 8 weight percent Ni, a method for producing such alloys, and devices comprising such an alloy body. The method comprises a low-temperature anneal in the (.alpha.+.gamma.) region of the Fe-Cr-Ni phase diagram. Inventive alloys typically have a coercive force H.sub.c no more than about 3.0 Oe, preferably no more than about 2.0 Oe, a maximum permeability .mu..sub.m of at least about 1500 G/Oe, preferably at least about 2500 G/Oe, and contain at least about 5 volume percent non-.alpha.-phase material, typically .alpha.'- and .gamma.-phase material. Inventive alloys typically also have yield strength to 0.2% offset of at least about 26.10.sup.7 Pa (40.10.sup.3 psi), elongation to fracture of at least about 15%, good formability and rust resistance. Alloys according to the invention can advantageously be used in devices comprising a magnetically soft body, for instance, in electro-acoustic transducers, e.g., in telephone receivers, recording heads, pole pieces, and armatures.

Growing community of inventors

New Providence, NJ, United States of America

Richard C Sherwood