Studies of High-Tc Superconductors and Molecular Materials under Extreme Hydrostatic Pressure

Washington University, Saint Louis MO

Investigators

Abstract

Despite enormous efforts, high-temperature superconductors have yet to fulfill the vaunted expectations placed in them. There exists neither a good basic understanding of these materials, nor the ability to process them for many potential applications. Progress has been impeded by the complexity of the perovskite-like structure and the important influence of defects. This individual investigator award will fund a project to study the temperature- and pressure-activated defect relaxation processes in both bulk high-Tc materials and their grain boundaries. The knowledge gained will help develop strategies to optimize the superconducting properties, in particular the current carrying capacity, and stabilize them for long-term applications. In addition, by suppressing the relaxation processes in a low-temperature experiment, the intrinsic dependence of Tc on pressure will be determined over a broad range of lattice parameter and carrier concentration, thus allowing a meaningful test of theory and perhaps pointing the way to higher values of Tc. High-pressure experiments on molecular magnets and superconductors are also planned. The research will involve a collaboration with a Russian scientist. Graduate and undergraduate students working on this project will benefit from the exposure to international collaborations as well as learn skills that will prepare them for future scientific careers. %%% High-temperature superconductors have yet to fulfill the vaunted expectations placed in them after their discovery nearly 15 years ago. Only a few specialized applications have reached the marketplace. Progress has been impeded by the complicated structure of these materials and the presence of many kinds of structural defects. Some of these defects can even migrate around at room temperature, thus degrading important properties, such as the current carrying capacity. This individual investigator award will fund a project to study the properties of mobile defects and try to develop a strategy to prevent their migration. This will open the door to further applications and also permit a better understanding of why these materials are superconducting at such high temperatures and perhaps point the way toward superconductivity at much higher temperatures. The research will involve a collaboration with a Russian scientist. Graduate and undergraduate students working on this project will benefit from the exposure to international collaborations as well as learn skills that will prepare them for future scientific careers. ***