Nonlinear Electrodynamics Of High Temperature Superconductors

These lectures are concerned with the application of high temperature superconductors to both passive and active high-frequency devices. The central issue addressed is the electrodynamics of granular superconductors, particularly where grain boundaries (either natural or synthetic) act as Josephson weak-links. Grain boundaries are responsible for residual dissipation and for unwanted dependence of the electromagnetic properties on ambient magnetic fields and on elevated power level. Properly controlled, similar weak-links are the key to high sensitivity dc and rf SQUIDS at readily accessible temperatures, and to modulators, mixers and detectors. Such structures may conveniently lead to superconductive electronic devices as well as coherent sources of radiation in the very far infrared. Contents:High Temperature SuperconductorsTheories of SuperconductivityElectro-dynamicsSuperconducting Phase and Flux QuantaMagnetic Resonance and RelaxationFlux Pinning, Creep and FlowFilm Transmission Lines and ResonatorsWaveguides and Cavity ResonatorsElectrodynamics of Type II SuperconductivityJosephson ElectrodynamicsGranular SuperconductivityElectrodynamics of Intergranular JunctionsMicrowave Absortion in Transient Magnetic FieldsNonlinear Microwave ElectrodynamicsMicrowave Processes and Quantum Interference Readership: Physicists, electrical engineers and materials scientists. keywords: “… Electrodynamics of High Temperature Superconductors will be of great value to practical specialists who wish to make devices or measurements using the electrodynamic properties of these materials. It is carefully and thoroughly grounded in the known and is a workmanlike job.” American Scientist

“The Frontiers of Knowhledge (to coin a phrase) are always on the move. - day’s discovery will tomorrow be part of the mental furniture of every research worker. By the end of next week it will be in every course of graduate lectures. Within the month there will be a clamour to have it in the undergraduate c- riculum. Next year, I do believe, it will seem so commonplace that it may be assumed to be known by every schoolboy. “The process of advancing the line of settlements, and cultivating and c- ilizing the new territory, takes place in stages. The original papers are p- lished, to the delight of their authors, and to the critical eyes of their readers. Review articles then provide crude sketch plans, elementary guides through the forests of the literature. Then come the monographs, exact surveys, mapping out the ground that has been won, adjusting claims for priority, putting each fact or theory into its place” (J. M. Ziman, Principles of the Theory of Solids (Cambridge University Press, 1972) p.v). The main purpose of the book is to present the mechanism of - perconductivity discovered in 1986 by J. G. Bednorz and K. A. Müller, and to discuss the physics of superconductors. The last chapter of the book presents analysis of tunneling measurements in cuprates. The book is - dressed to researchers and graduate students in all branches of exact sciences.

Unlike direct problems related to the solution of differential equations, inverse problems are typically expressed by integral equations. These equations relate media parameters to parameters of a measured signal, or input parameters to output ones in various measurement systems. The solution of integral equations is, with few exceptions, an ill-posed problem, and additional a priori information about the exact solution should be used to solve such problems. The specific character of the a priori information determines various regularisation methods that are in use here to obtain an approximate solution: Tikhonov's method, statistical regularisation method, methods based on the use of additional equations or restrictions or of models with limited number of unknown parameters. The main point of this book is the study of convergence properties of each method and the wide application of numerical modelling that gives the accuracy of the solution in a chosen metric. It is an unaccustomed procedure for physicists, but, because there is no proportionality between data and solution errors in ill-posed problems, such approach is inevitable.

Visualisation of Shubnikov Phase Using the High Resolution Faraday Effect; Mechanism of microwave Absorption and Flux Distribution in High Temperature Superconductors; Field Penetration and Magnetisation of Hts; Experimental Aspects of Megnetisation Studies in Superconductors; Recent Development of the Critical State Model; Anomalous Magnetisation in Ybacuo Single Crystals; Surface Barrier and Fish Tail; Low Field Magnetic Behaviour of High Temperature Superconductors; Irreversible Part of Magnetisation Due to Flux Pinning; Irreversibility Line in High Temperature Superconductors; Non-Linear Flux Flow Regime High-Temperature Superconductors.