Two topics in the forefront of superconductor research--superconductor-insulator transition in thin films and vortex tunneling in granular, bulk, and high temperature superconductors--have never before been given a unified and deductive treatment. This monograph and text provides a much-needed, comprehensive introduction to the theory of quantum fluctuations in inhomogenous superconducting materials. It be will be of great use to students and researchers in disciplines such as superconductivity, many-body systems, phase transitions, submicron physics, and surface science.

In this text experts review experimental studies that directly reveal the relationship between the atomic structure and physical behavior of high-Tc superconductors. The thorough discussion centers on twins, twin boundaries, the vortex lattice, and magnetic and mechanical properties in connection with structural imperfections. Particular attention is paid to the role of the oxygen atom in the Y-Ba-Cu-O and La-Cu-O species. The experimental methods evaluated include electron and X-ray diffraction, electron microscopy, and M|ssbauer spectroscopy. This book makes extraordinarily valuable data obtained at the Institute of Solid State Physics at Chernogolovka accessible to the wider international community of researchers in superconductivity.

A broad introduction to high Tc superconductors, their parent compounds and related novel materials, covering both fundamental questions of modern solid state physics (such as correlation effects, fluctuations, unconventional symmetry of superconducting order parameter) and applied problems related to short coherence length, grain boundaries and thin films. The information that can be derived from electron spectroscopy and optical measurements is illustrated and explained in detail. Descriptions widely employ the clear, relatively simple, phenomenological Ginzburg-Landau model of complex phenomena, such as vortex physics, vortex charge determination, plasmons in superconductors, Cooper pair mass, and wetting of surfaces. The first comprehensive reviews of several novel classes of materials are presented, including borocarbides and chain cuprates.

Other work contributing to this thesis is focused on a cuprate superconductor, Bi 2- y Pb y Si 2 CuO 6+ [delta] . With the density of states (DOS) maps at both zero and nonzero magnetic fields, a division normalization method is applied to separate two characteristic energy scales. We extract a homogeneous hidden small gap coexisting with an apparent inhomogeneous gap. Compared with a recent experiment performed by Boyer et al. , the hidden small gap is believed to be a superconducting order and the apparent inhomogeneous gap is referred to the pseudogap phase. Under the magnetic field range in our experiment, a vortex liquid state is proposed. This technique can be extended to detect the possible superconducting information in the Nernst state above Tc .

Physics of High-Tc Superconductors highlights the important experiments that provide insights on the concept of high-temperature superconductors. Composed of 11 chapters, this book covers the theories and materials of these superconductors. The opening chapters of this book deal with the concepts at the cutting edge of materials science and the technical details of electron-phonon interaction calculations and their application to high-Tc superconductors. The subsequent chapters describe the various features of the atomic and electronic structure of high-Tc superconductor materials, such as quaternary, metallic, and pseudoperovskite copper oxides. These topics are followed by descriptions of the isotope effect, lattice vibrations, and optical spectra of high-Tc superconductor materials. The discussion then shifts to tunneling, relaxation, and morphological studies of these materials. The concluding chapter focuses on the superconductivity potential of bismates and thallates. Undergraduate materials science students will find this book invaluable.

Physics and Materials Science of High Temperature Superconductors, II represents the results of a fruitful dialogue between physicists and materials scientists which took place under the auspices of a NATO Advanced Study Institute in Porto Carras, Greece, between 18 and 31 August, 1991. It builds on and carries forward the success of NATO ASI 181 published in 1990. The theoretical side of the discussions reveal the basic premise of the phenomenological and Ginzburg-Landau theories of superconductivity, the implications of short coherence length, long penetration depth, the melting of flux lattices, and other matters, while the materials science includes discussions of microstructures, local inhomogeneities, deviations from ideal chemistry, the effects of systematic errors in materials preparation, the definition of imperfections, and the utilization of common materials analysis techniques. The reader will be made aware of the potential significance of Angstrom scale structural and chemical details, and the need to consider basic theoretical concepts when designing procedures to process viable, solid conductors, specifically the effects of oxygen stoichiometry and deviations from it, as well as the microstructural demands on pinning in the light of very short coherence lengths.