Anisotropy Effects in Superconductors

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.