Anisotropy Effects in Superconductors

ISBN-13: 9781468407839 / Angielski / Miękka / 2012 / 316 str.

Harald Weber

Opis

Considering the enormous progress achieved in some special areas of superconductivity during the last few years, it seemed worthwhile to discuss thoroughly a subject, which has encountered severe pro blems on the theoretical and the experimental side, namely the effects of the anisotropic electron and phonon properties of (single crystalline) materials on the characteristic features of the super conducting state. The fact that the majority of scientists actively engaged in this research field at present were brought together at the meeting, has led to an almost complete coverage of the pertinent topics in this volume. Six review papers discuss the development and the present state of theory and experiment concerning the anisotropies of the upper critical field and the magnetization as well as the flux line lattice and the superconducting energy gap. Furthermore, 18 papers present the most recent research on these properties and additional anisotropy effects associated with the intermediate state patterns or the specific heat. Concerning the magnetic properties, remarkable agreement between theory and experiment has been achieved; on the other hand, controversial views regarding the existence of anisotropy in the superconducting energy gap are presented. In both cases, how ever, theorists and experimentalists are still confronted with a number of open questions. It is the purpose of this book to draw the attention of scientists to these fascinating problems. Harald W."

Spis treści

1. The Upper Critical Field.- R-1 On the Theory of Macroscopic Anisotropy Phenomena in Type-II Superconductors.- R-2 Experimental Investigations on the Anisotropy of the Upper Critical Field in Type-II Superconductors.- 2. Hc2 and Related Properties.- C-1 The Influence of Fermi Surface Anisotropy on Hc2(T).- C-2 Impurity Dependence of Hc2 Anisotropy in Niobium.- C-3 Microscopic Anisotropy Parameters of Niobium.- C-4 Anisotropy of Hc2 in PbTl-Alloys.- C-5 Comments on Hc2 at Low Temperatures.- C-6 The Influence of Magnetic Anisotropy on the Properties of Niobium in the Mixed State.- C-7 Anisotropy of the Stress Dependence of Critical Parameters in Uniaxial Superconductors.- 3. Flux Lines.- R-3 Magnetization and Flux Line Lattice in Anisotropic Superconductors.- R-4 Morphology of Flux Line Lattices in Single-Crystalline Type-II Superconductors.- 4. Flux Lines, Domains and Magnetization.- C-8 Correlations between Flux Line Lattice and Crystal Lattice.- C-9 Experiments on the Correlation between the Flux Line Lattice and the Crystal Lattice in Superconducting Lead Films.- C-10 Anisotropy in the Intermediate State of Superconducting Mercury.- C-11 Mixed State Anisotropy of Superconducting Vanadium.- C-12 Measurement of Torque due to Anisotropy of the Magnetization Vector in Superconducting Niobium.- 5. Energy Gap.- R-5 Microscopic Calculations of Energy Gap Anisotropy.- R-6 An Evaluation of the Validity of Superconducting Evidence for Anisotropy and Multiple Energy Gaps.- 6. Energy Gap and Related Properties.- C-13 Tunneling Junction Phenomena: An Answer to Unanswered Questions.- C-14 An Analysis of Evidence for Superconducting Energy Gap and Pairing Interaction Anisotropy for Two Types of Experiments.- C-15 A Nearly Free Electron Model of the BCS Gap Equation: Energy Gap Anisotropy in Gallium.- C-16 Specific Heat of Superconducting Zinc.- 7. Other Topics.- C-17 Unusual Resistance Effect Shown in a Periodic S-N-S System (Pb-Sn Lamellar Eutectic).- C-18 The Upper Critical Field of Superconducting Polysulfur Nitride, (SN)x — (Abstract only).- List of Participants.- Author Index.