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.

The publication of Volume V of Physical Properties of High Temperature Superconductors is expected in March, 1996. It will have chapters of interest for both fundamental studies and applied research. The topics discussed are expected to include the electromagnetic response (penetration depth and surface resistance), local lattice distortions, the influence of vortex fluctuations on macroscopic behavior, the properties of superlattices, and the symmetry of the superconducting order parameter.

Studies Of High Temperature Superconductors Volume 29 -- Advances In Research & Applications

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.