Critical Currents In Superconductors

This proceedings volume reviews the recent developments of superconducting materials for practical applications and critical current characteristics. It contains 18 invited papers and 72 contributed papers. The scope of these papers includes: (1) synthesis and processing of practical materials, (2) properties of high-Tc tapes, coils and bulk materials, (3) critical currents and microstructure, (4) flux dynamics and pinning mechanisms, (5) applications of high-Tc materials, (6) applications of low-Tc superconductors, (7) processing, physical properties and applications of high-Tc thin films.

Applications of superconductivity at the boiling temperature of liquid nitrogen continue to challenge physicists, materials scientists and engineers all over the world eight years after the discovery of high temperature superconductivity. The key to a solution of today's problems lies in the optimization of the defect structure in well-oriented oxide materials as well as in a fundamental understanding of the magnetic microstructures in the mixed state and how they are affected by the crystallographic nature ('dimensionality') of these materials. Fifteen invited overview lectures as well as approximately 150 contributed papers highlight the state of the art in this important field of superconductivity and review our current knowledge of critical currents in superconductors.

Introduction to Superconductivity differs from the first edition chiefly in Chapter 11, which has been almost completely rewritten to give a more physically-based picture of the effects arising from the long-range coherence of the electron-waves in superconductors and the operation of quantum interference devices. In this revised second edition, some further modifications have been made to the text and an extra chapter dealing with ""high-temperature"" superconductors has been added. A vast amount of research has been carried out on these since their discovery in 1986 but the results, both theoretical and experimental, have often been contradictory, and seven years later there remains little understanding of their behavior. This book comprises 14 chapters, with the first focusing on zero resistance. Succeeding chapters then discuss perfect diamagnetism; electrodynamics; the critical magnetic field; thermodynamics of the transition; the intermediate state; and transport currents in superconductors. Other chapters cover the superconducting properties of small specimens; the microscopic theory of superconductivity; tunneling and the energy gap; coherence of the electron-pair wave; the mixed state; critical currents of type-II superconductors; and high-temperature superconductors. This book will be of interest to practitioners in the fields of superconductivity and solid-state physics.

This workshop includes about 110 papers describing the flux pinning and related electromagnetic phenomena in superconductors. Various problems are argued on exotic properties of flux lines, flux dynamics, flux pinning mechanisms, critical current density and critical state phenomena in both high- and low-temperature superconductors. Contents:OverviewsFlux Lines, Phase DiagramsIrreversibility Line, Flux DynamicsFlux Spinning Properties, Artificial PinsBulk Materials, Tapes, Thin Films Readership: Researchers and postgraduates students in high Tc superconductivity, condensed matter/solid state physics, applied physics, electrical & electronic engineering and materials science.

This book covers the flux pinning mechanisms and properties and the electromagnetic phenomena caused by the flux pinning common for metallic, high-Tc and MgB2 superconductors. The condensation energy interaction known for normal precipitates or grain boundaries and the kinetic energy interaction proposed for artificial Nb pins in Nb-Ti, etc., are introduced for the pinning mechanism. Summation theories to derive the critical current density are discussed in detail. Irreversible magnetization and AC loss caused by the flux pinning are also discussed. The loss originally stems from the ohmic dissipation of normal electrons in the normal core driven by the electric field induced by the flux motion. The influence of the flux pinning on the vortex phase diagram in high Tc superconductors is discussed, and the dependencies of the irreversibility field are also described on other quantities such as anisotropy of superconductor, specimen size and electric field strength. Recent developments of critical current properties in various high-Tc superconductors and MgB2 are introduced. The 3rd edition has been thoroughly updated, with a new chapter on critical state model. The mechanism of irreversible properties is discussed in detail. The author provides calculations of pinning loss by the equation of motion of flux lines in the pinning potential and hysteresis loss. The readers will learn why the resultant loss is of hysteresis type in spite of such mechanism. This book aims for graduate students and researchers studying superconductivity as well as engineers working in electric utility industry.

This volume will focus on the theory and experiments leading to quantitative understanding of the magnetic field and temperature dependence of critical current densities in high-temperature superconductors. Topics will include: critical currents and flux-pinning, flux flow and flux creep, anisotropy of critical fields and currents, properties of the flux lattice and the irreversibility line, magnetization, granularity. Contents:Critical Currents in Neutron Irradiated High Temperature Superconductors (H W Weber)Radiation Induced Disorder as a Unique Method for Studing Electronic States of HTSC's and Modifying Their Properties (B N Goshchitskii et al)Influence of Fast Neutron Irradiation on Various Types of HTSC Materials: Comprehensive Study (H Szymczak et al)Critical Currents and Angular Dependence in Magnetic a.c. Response: Test for Intrinsic Pinning (L Krusin-Elbaum et al)Why the Critical Current Densities of High Tc's Vary Anomalously with Temperature, Field and Time (S Senoussi et al)The Effect of the Intragranular Irreversible Magnetization on the Intergranular and Intragranular Critical Currents (S L Ginzburg et al)Bean-Livingstone Surface barrier in High Temperature Superconductors (M Konczykowski)Pinning Centers in C-Axis Oriented Bi-Sr-Ca-Cu-O Thin Films (G Jung et al)The Effect of an Electric Current on Microwave Absorption in a YBaCuO Ceramic Superconductor (J Stankowski et al)and other papers Readership: Condensed matter physicists, electronic and electrical engineers and chemists. keywords: