This NATO Advanced Research Workshop was held at a time when there was little consensus as to the mechanism for high temperature superconductivity, in the context of a world undergoing major changes in its political alignments and sense of the possibility for the future. It was characterized by generosity in the sharing of our uncertainties and speculations, as was appropriate for both the subject matter and the context. The workshop was organized, of necessity around the experimental work, as is this volume. Where the theoretical work is directly relevant to particular experiments, it is included in the appropriate sections with them. Most of the participants felt strongly that magnetic fluctuations played an important role in the mechanism for high T c, although with the exception of the IlS R work reported by Luke showing results inconsistent with the anyon picture, and the work on flux phases by Lederer, the mechanism remained an issue in the background. A major focus was the phenomenological interpretation of the NMR data.

These Proceedings of a NATO-ARW (HTECH ARW 96 00 52) held at the International Center for Theoretical Physics, Trieste, Italy from Aug 5 till Aug 9, 1996 resulted from many discussions between various workers, concerning the need for a gathering of all (if possible) who were concerned about the subject of superconductivity fluctuations in High critical Temperature Superconductors (HTS). It appeared to many that the Skocpol-Tinkham work of 1975 had to be revitalized in view of the discovery of the new superconducting ceramics and the enormous amount of work having already taken place. The study of HTS is one of the most prominent research subject in solid state sciences. The understanding of the role of fluctuations is also thought to be necessary before technological applications since the fluctuations may destroy the superconducting state. The workshop discussions have touched upon (i) Superconducting fluctuations in the vicinity of the critical transition, (ii) Superconductivity fluctuations near the percolation transition, and (iii) Fluctuations of the vortex lattice at the lattice melting temperature. These topics served as initiators for a very great amount of discussions with many comments from the audience. More than forty "long lectures" and two "poster sessions" were held. Private discussions going unrecorded but obviously took place at many locations : lecture halls, staircases, cafetaria, bedrooms, bars, beach, . . .

Physical & Material Properties of High Temperature Superconductors

High Temperature Superconductivity provides a broad survey of high temperature superconductivity, discussing the adaptations of experimental and theoretical techniques and methods that take advantage of the revolutionary properties of high temperature superconductors. Distinguished engineers, chemists, and experimental and theoretical physicists introduce their own particular area of the field before going on to explain current theories and techniques. The book is divided into three sections: materials, mechanisms, and devices. Topics covered include synthetic approaches to the growth of new materials; optical, magnetic, and electrical characterization of synthesized materials; strong correlations; the magnon pairing mechanism; and technical background of device performance in new materials. A coherent introduction to high temperature superconductivity, this volume will be invaluable to researchers in condensed matter physics, chemistry, materials science, and engineering.

High temperature superconductors have received a great deal of attention in recent years, due to their potential in device and power applications. This book summarises the materials science and physics of all the most important high temperature superconductors as well as discussing material growth, properties and applications.Part one covers fundamental characteristics of high temperature superconductors and high TC films such as deposition technologies, growth, transport properties and optical conductivity. Part two is concerned with growth techniques and properties of high temperature superconductors, including YBCO, BSCCO and HTSC high TC films, and electron-doped cuprates. Finally, part three describes the various applications of high temperature superconductors, from Josephson junctons and dc-superconductive quantum inference devices (dc-SQUIDs) to microwave filters.With its distinguished editor and international team of contributors, this book is an invaluable resource for those researching high temperature superconductors, in industry and academia. In light of the many recent advances in high temperature superconductors, it will benefit physicists, materials scientists and engineers working in this field, as well as in areas of industrial application, such as electronic devices and power transmission. - Summarises the materials science and physics of all the most important high temperature superconductors - Discusses material growth, properties and applications - Outlines fundamental characteristics of high temperature superconductors and high TC films

During the past 30 years materials science has developed into a full-fledged field for basic and applied scientific enquiry. Indeed, materials scientists have devoted their efforts to creating new materials with improved electronic, magnetic, thermal, mechanical, and optical properties. Often unnoticed, these new materials are rapidly invading our homes and automobiles, and may be found in our utensils, electronic equipment, textiles, home appliances, and electric motors. Even though they may go unnoticed, these new materials have either improved the efficiency and lifetime of these items or have reduced their weight or cost. In particular, magnetically ordered materials are useful in various applications, such as motors, magnetic imaging, magnetic recording, and magnetic levitation. Hence, much effort has been devoted to the development of better hard magnetic materials, magnetic thin films, and molecular magnets. During the same period of time, Mossbauer-effect spectroscopy has grown from a laboratory curiosity to a mature spectroscopic technique, a technique that probes solid-state materials at specific atomic sites and yields microscopic information on the magnetic and electronic properties of these materials. Iron-57 is the most commonly and easily used Mossbauer-effect isotope and, of course, is particularly relevant for the study of magnetic materials. Various applications of Mossbauer spectroscopy to magnetic materials are discussed in the first six chapters of this volume. Other isotopes such as zinc-67 and gadolinium-ISS have recently been used to study the electronic properties of zinc compounds and the electronic and magnetic properties of rare-earth transition metal compounds.

Since the discovery in 1986 of high temperature superconductors by J. G. Bednorz and K. A. Müller, a considerable progress has been made and several important scientific problems have emerged. Within this NATO Advanced Study Institute our intention was to focus mainly on the controversial topic of the symmetry of the superconducting gap and given the very short coherence length, the role of fluctuations. The Institute on ‘The Gap Symmetry and Fluctuations in High- Superconductors’ took place in the “Institut d’Etudes Scientifiques de Cargèse” in Corsica, France, between 1 - 13 September 1997. The 110 participantsfrom 18 countries (yet 30 nationalities) including 23 full time lecturers, have spent two memorable weeks in this charming Mediterranean resort. All lecturers were asked to prepare pedagogical papers to clearly present the central physical idea behind specific model or experiment. The better understanding of physics of high temperature superconductivity is certainly needed to guide the development of applications of these materials in high and weak current devices.