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TT: Tiefe Temperaturen

TT 15: Grundlegende Experimente zur Supraleitung

TT 15.2: Invited Talk

Wednesday, March 29, 2000, 15:30–16:00, H20

High-tech calorimetry and crystals in high temperature superconductors: solved and unsolved problems. — •Alain Junod, Andreas Erb, Yuxing Wang, and Frederic Bouquet — Department of physics of condensed matter, University of Geneva, CH-1211 Geneva 4 (Switzerland)

The quest for a better understanding of high temperature superconductors has been the driving force toward an improvement of numerous experimental techniques, among which calorimetry and crystal growth. The joint effort of several research groups has provided samples of unprecedented purity, specific heat experiments with an order-of-magnitude progress in resolution and sensitivity in very high magnetic fields, with promising developments in the direction of very high pressures. Quite unexpectedly, the number of problems that have been solved using these impressive tools is comparable to the number of new puzzles that have emerged. We review a few of them: universality class of the superconducting transition, unconventional pairing symmetry, "fishtail" effect and melting of the vortex lattice.