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Magnetics, IEEE Transactions on

Issue 2 • Date March 1987

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Displaying Results 1 - 25 of 343
  • [Front cover and table of contents]

    Page(s): 0
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    Freely Available from IEEE
  • ACS-86 Editorial

    Page(s): 347
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    Freely Available from IEEE
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  • Early superconductivity research (except Leiden)

    Page(s): 371 - 375
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    Experiments and theories in the period between Meissner and Ochsenfeld (1933) and Bardeen, Cooper and Schrieffer (1957) are reviewed, with special emphasis on the development of phenomenological models of superconductivity. View full abstract»

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  • Origins of the theory of superconductivity

    Page(s): 376 - 379
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    A personal account is given of the events that led to the theory of superconductivity. View full abstract»

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  • Superconducting tunneling spectroscopy and the observation of the Josephson effect

    Page(s): 380 - 389
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    The discoveries associated with superconducting tunneling spectroscopy, its development with W. L. McMillan as a tool to measure the electron-phonon interaction in superconductors, and the first observation of the Josephson effect are described from a personal point of view. View full abstract»

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  • Niobium superconducting magnets

    Page(s): 390 - 395
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    The process of design and construction, in 1954, of the first superconducting magnet is described. That magnet had Nb windings on an Fe core. It produced .71T in a small gap at 4.2K. Other Nb magnets, both with and without Fe, were built at several laboratories. Some of them are described, along with the applications to which a few were put. Empirically, it was clear in the 1950s that the performance of Nb as magnet wire was spectacularly improved by cold work. View full abstract»

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  • Recollection of events associated with the discovery of high field-high current superconductivity

    Page(s): 396 - 402
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    In this article, an attempt is made by the author to recall some of the more important events that led to the discovery of high field-high current superconductivity. After a little background, events are recalled from a few years before, until shortly after the discovery. Considerable attention is given to people events, thus emphasizing the human side of the period, as recalled by the author. View full abstract»

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  • Type II superconductivity: Quest for understanding

    Page(s): 403 - 412
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    By 1941, many of the essential experimental features of type II superconductivity had already been observed (de Haas and Voogd, Shubnikov et al., Keesom and Desirant). Moreover, truly remarkable progress had been made toward theoretical understanding based on negative interphase surface energy considerations (Gorter, H. London). However, a competing explanation, the filamentary sponge model, was proposed (Mendelssohn) in all attempt to explain magnetic hysteresis effects which tended to obscure the intrinsic thermodynamic character of type II superconductivity. This filamentary sponge model is now known to be of only very restricted applicability, but for more than two decades it enjoyed wide acceptance, so much so, that when the ultimate theoretical basis for type II superconductivity was formulated in the 1950's (Ginzburg and Landau, Abrikosov, Gorkov (GLAG)), it was largely ignored. With the discovery of the practical supermagnet potential of type II superconductors (Yntema, Kunzler et al.), interest in achieving deeper understanding of-high-magnetic-field superconductivity was reawakened. Only then was the power of the GLAG formalism very belatedly recognized, both with respect to near-ideal type II superconductors (Goodman) and with respect to non-ideal materials of technical interest (Berlincourt and Hake). Rapid experimental and theoretical progress followed on a number of significant aspects, including flux trapping, flux creep, and flux flow (Yntema, Anderson, Kim, Hempstead, Strnad), and surface superconductivity (Saint-James and de Gennes). Indirect "observation" of Abrikosov's vortex lattice was soon accomplished by neutron scattering techniques (Cribier et al.) and by nuclear magnetic resonance techniques (Pincus et al.). Finally, a more direct magnetic decoration technique (Essmann and Trouble) yielded remarkably graphic and incontrovertible pictoral confirmation of the Abrikosov vortex lattice. View full abstract»

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  • The argonne bubble chamber supermagnet

    Page(s): 413 - 415
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    The winding of the 12 ft. bubble chamber magnet is 16 ft. in diameter, 10 ft. tall, and weighs 50 tons. The magnet cryostat weighs another 50 tons and the iron return path has a weight of 1600 tons. It produces a field of 1.8 tesla and was first tested in December of 1968. After working for more than ten years at Argonne it was moved to the Stanford Linear Accelerator (SLAC) and became a part of the detector for a colliding electron beam experiment. View full abstract»

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  • International cooperative--collaborative perspectives - Superconductive science and technology

    Page(s): 423 - 426
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    This paper discusses the achievements of Applied Superconductivity over the past 25 years and a brief outline of the present technical and commercial status of the field. Special attention is paid to the role of International collaboration and cooperation in superconducting research. The main topics covered include applications of superconductivity to Energy Technology, Particle Physics, Medical Equipment and Electronics. Natural resource limitations are discussed and some future application areas are suggested. View full abstract»

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  • Collaborative superconductivity research in Europe

    Page(s): 427 - 433
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    The collaboration in Europe for research in superconductivity, especially for large Scale applications, has a long tradition. In the early seventies already a so-called "GESSS group" (Group on European Superconducting System Studies) became active for accelerator and detector magnet development. In the second half of the seventies the fusion technology programme in Europe called for an increasing effort in magnet development. Due to the fact that the fusion work is at all a collaborative European effort and the earlier GESSS laboratories got involved in that area too, these activities were carried out jointly from the beginning. Participation in the IEA-Large Coil Task by two European groups also proved the capability of an even broader international collaboration. Based on the different management schemes for the collaborations lessons have been learned and are discussed, which might be valuable for foreseeable large European projects such as NET (Next European Torus) and LHC (Large Hadron Collider) in the next decade. The role of industry as a collaboration partner in the different areas is discussed, too. View full abstract»

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  • Opportunities for international collaboration in superconducting electronics

    Page(s): 434 - 435
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    It is said that international collaborations in superconducting electronics have become particularly important to share research risks and resources. The present status of technologies, recent cooperative research activities, and some comments on future cooperations in superconducting electronics are described. View full abstract»

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  • Cosmic-ray monopole search at IBM-BNL using superconducting induction detectors

    Page(s): 441 - 449
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    Supermassive magnetic monopoles are an inevitable consequence of all Grand Unified Theories (GUT's). They would have originated in the very hot early universe some 10-35sec. after the Big Bang when the unified force split apart into the strong and electroweak forces. Over thirty laboratories throughout the world have constructed or are presently constructing detectors to search for such primordial monopoles in cosmic rays. This paper, partly tutorial, reviews the past monopole detector work at IBM and describes the present effort to set-up at the Brookhaven National Laboratory a large-area superconducting induction detector. Two detectors are being built based upon the high-order gradiometer, fully coincident, closed-box design previously developed at IBM. The first, utilizing an existing magnet-testing dewar at BNL, is a rectangular parallelopiped detector of 1.0 m2effective area (averaged over 4π sr for isotropie flux) being built to test the feasibility of large area schemes in preparation for construction of a much larger 4.0 m2octagonal prism detector. The latter could serve as the prototype for an array of detectors to reach the Parker bound on monopole flux set by the existence of the 3 μG galactic magnetic field in several years of operation. View full abstract»

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  • Variation of the electrochemical potential difference in a gravitational field

    Page(s): 450 - 453
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    We have determined the variation of the electrochemical potential difference in a gravitational field, and the results agree to within 4% with the predictions of the Equivalence Principle (EP). Thus, EP has again been verified, but unlike previous experiments, this experiment involved charged particles. The results were obtained using a DC SQUID in which the two junctions were separated vertically by about 7 cms. The junctions, which were phase-locked to an external microwave source, acted as two very precise batteries. Because of the gravitational red-shift of the radiation, a voltage difference of 1:1017existed between these batteries, giving a net EMF in the SQUID loop in the absence of other effects of about 2×10-21volts. The loop EMF determined by the rate of change of flux in the loop was however less than 1×10-22volts, thus demonstrating the additional variation in the potential difference due to the gravitational field. View full abstract»

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  • Long term operation of low noise DC-SQUID coupled to a very high Q gravitational radiation detector

    Page(s): 454 - 457
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    We have coupled a very low noise dc-SQUID to the gravitational radiation detector of the Rome group at CERN laboratories. The SQUID used is a multiloop thin-film device with an input inductance of 1.6 μH, loop inductance of 5 pH and coupling coefficient of 0.5. The gravitational radiation detector is composed by a 2.3 tons Aluminum cylinder mechanically coupled to a resonant capacitive transducer; this is matched to the SQUID by means of a large superconducting transformer. The signal to be detected is essentially composed by the two mode frequencies at about 1 kHz and with quality factors of the order of 4×106. To operate in a closed feedback loop mode we have used a particular setup in order not to degrade the performance of the system. The system operated for seven months with some interruptions due to refilling of liquid helium and various tests on the apparatus. The flux noise obtained was 1.5 to3times10^{-6} Phi_{o}/sqrt{Hz}at 1 kHz with a linearity over 6 orders of magnitude and a long term stability of1.5 times 10^{-8} Phi_{o}/hour. View full abstract»

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  • Use of the Josephson junction in fundamental quantum electronics experiments

    Page(s): 458 - 464
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    The Josephson junction provides two strong nonlinearities, the Josephson inductance utilized in parametric amplification and the sharp resistive knee used in SIS mixing. Both of these nonlinearities can be strong compared to a characteristic quantum current or voltage scale. This opens the possibility of using Josephson junctions to carry out fundamental experiments in quantum electronics that would be difficult or impossible to carry out at optical frequencies due to the lack of a correspondingly large nonlinearity in optical media. Here we propose a number of such experiments ranging from the generation of squeezed states with Josephson-parametric amplifiers to the generation of quantum-mechanical superpositions of macroscopically distinguishable states via Josephson-transmission lines. How the properties of such states can be investigated using SIS mixers will also be described. Squeezed states may be technologically useful in sensitive and precision measurement. How such states can be used to enhance interferometer sensitivity or reduce noise in phase sensitive measurement will also be described. View full abstract»

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  • Measuring magnetic fluctuations from seismic waves using a superconductive gradiometer

    Page(s): 465 - 468
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    We present a new application of superconductive magnetic gradiometry to a geophysical problem. Changing stresses in the earth's crust produce magnetic variations through the piezomagnetic effect. Seismic wave stress fluctuations cause magnetic variations measurable by a superconductive gradiometer. Their magnitude depends both on the wave stress and on the ambient stress. Measurements repeated over time can monitor changes in the ambient stress of magnetic strata near earthquake faults. Estimates of the signal size expected from the sources used in seismic surveying show that they comfortably exceed the sensitivity limits of present-day superconductive magnetic gradiometers. A first field trial of the method, conducted in the Whipple Mountains near Parker, AZ, in November 1985, shows magnetic gradient fluctuations several pT/m in amplitude coincident with the passage of seismic waves. However, ground motion can excite mechanical resonances in the gradiometer that contaminate the signal. The field trial points the way to refinements that lead to suppression of interference from ground motion. View full abstract»

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  • Acoustic detection of single particles for neutrino experiments and dark matter searches

    Page(s): 469 - 472
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    We are developing an entirely new type of particle detector, called a silicon crystal acoustic detector (SiCAD), which senses ballistic phonons generated when an incident particle collides with a nucleus or electron in a cube of crystalline silicon. For events which deposit energy greater than about 1 keV, a 1 kg SiCAD would have spatial resolution better than 1 mm3and energy resolution better than 100 eV. We describe our laboratory research utilizing carbon thermistors, superconducting transition edge devices, and superconducting tunnel junctions as phonon sensors on the crystal faces. View full abstract»

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  • Design and operation of SQUID-based planar gradiometers for non-destructive testing of ferromagnetic plates

    Page(s): 473 - 476
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    A planar second-order gradiometer coupled to a SQUID has been used with a persistent mode coil generating 0.02T perpendicular to a steel plate for the detection and characterisation of defects, such as cracks. We outline design criteria for the system, which is contact free, allows stand-off distances of up to 10cm, and can accommodate intervening media, both insulating (e.g. concrete) or conducting (e.g. sea-water or aluminium cladding). The sensitivity limit appears to be set by long-range permeability variations in the material of the plates, which may be due to unrelieved stress. We explain the use of digital filtering techniques to improve the resolution. Finally we discuss the use of higher-order gradiometers to improve the discrimination of localised defects from background variations. View full abstract»

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  • SQUID technology applied to the study of electrochemical corrosion

    Page(s): 477 - 479
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    Both the temporal and spatial dependences of the magnetic fields of electrochemical corrosion reactions have been investigated. A comparatively simple metal-electrolyte system, Zn in HCl, was chosen for concentrated study. Design of this corrosion cell, as well as its rationale, are described. The spectral density of the magnetic field generated by corrosion reactions has an inverse dependence on frequency. The overall noise level increases with increasing corrosion rate. These preliminary results confirm the great potential of SQUID magnetometry for the study of electrochemical corrosion phenomena. View full abstract»

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Aims & Scope

IEEE Transactions on Magnetics publishes research in science and technology related to the basic physics and engineering of magnetism, magnetic materials, applied magnetics, magnetic devices, and magnetic data storage.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Pavel Kabos
National Institute of Standards and Technology