Vortex Physics And Flux Pinning

Studies of High Temperature Superconductors, Volume 48 - Vortex Physics & Flux Pinning

Proceedings of the NATO Advanced Study Institute, Kusadasi, Turkey, July 26-August 8, 1998

A discussion by an assembly of expert physicists and materials scientists, embracing the specific features of vortex-pin interactions, the modes of different kinds of vortex motion under the action of Lorenz force, and the mechanisms of dissipation. The effects of transport and screening currents, superimposed AC magnetic fields and the microwave electromagnetic irradiation on vortex behaviour define the electromagnetic properties of a high-Tc superconducting material. The mechanisms driving the depinning of vortices and the dynamics of their motion determine the critical current density and its file dependence, the mechanisms of energy dissipation, and linear and nonlinear resistivity, AC losses, and noise in electronic circuitry. The book therefore has direct implications for the development of new devices and components in electrical engineering, modern electronics, computer technology, and microwave communication.

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 second edition has been brought up to date by the inclusion of an extensive new chapter on aspects relevant to high-temperature superconductors. The new edition provides researchers, engineers and other scientists with an introduction to the field and makes useful supplementary reading for graduate students in low-temperature physics.

Studies of High Temperature Superconductors, Volume 48 - Vortex Physics & Flux Pinning

Presents a modern treatment of the physics of vortex matter, mainly applied to unconventional superconductors and superfluids but with extensions to other areas of physics.

The idea for this book originated from an International Conference on Mag netic Structures in Superconductors organized by John R. Clem and the author at Argonne National Laboratory (ANL) in September of 1973. Large parts of the book evolved from lectures given to graduate students at the University of TUbingen during the past three years. It is the purpose of this book to provide an introduction to the many features of magnetic flux structures in superconductors and to discuss the this field. Here, in addition to the static proper recent developments in ties of magnetic flux structures, the time-dependent phenomena represent an important subject including flux flow and the transport effects in supercon ductors. Throughout the book the emphasis is placed on the physical phenom ena and the experimental results. We do not attempt a general introduction to superconductivity. Except for a brief discussion of the Ginzburg-Landau theory, with respect to the theoretical developments we only give an outline and refer to the original papers or other reviews for the detail of the calculations. The book is intended for researchers and graduate students interested in the subject of magnetic flux structures in superconductors. It may serve as supplementary material for a graduate course on low-temperature solid state physics. During recent years technological applications of supercon ducting materials are becoming increasingly important. Here the static and dynamic behavior of magnetic flux structures playa distinguished role. The book may be helpful for people envolved in these engineering aspects of superconductivity.