Fluctuations and Phase Transitions in Superconductors

University Of Maryland, College Park, College Park MD

Investigators

Abstract

This award will support an experimental study of the temperature vs. magnetic field phase diagram of type-II superconductors. The project's goal is to determine if there is a transition in non-zero field, and to determine the critical exponents of that transition if it exists, as well as the exponents of the zero-field transition. (The exponents reported in the literature vary widely for both transitions.) The methods used will be DC I-V and high-frequency (45 MHz to 45 GHz) conductivity measurements on the same samples, providing independent experiments. It is expected that this project will lead to a much-improved understanding of phase transitions in superconductors and in other systems. More broadly, the project will reaffirm that questioning and testing widely-accepted results is an essential part of the scientific process. An important part of this project is the support for training of graduate and undergraduate students. The PIs will continue their strong efforts to involve women and minorities in research, and to collaborate with scientists from Latin America and Eastern Europe. Finally, both PIs will continue their extensive efforts to encourage broader education in science, including work with predominantly minority public-school students. A superconductor, by definition, is a material that has no resistance to the flow of electricity, a property with great potential technological importance. Prior work showed that the consensus concerning the limits of superconductivity, in particular, whether materials are superconducting in a magnetic field, may have been incorrect. This award will support research that will more generally explore under what conditions superconductivity can exist. The project will reaffirm that questioning and testing widely-accepted results is an essential part of the scientific process. An important part of this project is the support for training of graduate and undergraduate students. Both PIs will continue their strong efforts to involve women and minorities in research, and to collaborate with scientists from Latin America and Eastern Europe. Finally, both PIs will continue their extensive efforts to encourage broader education in science, including work with predominantly minority public-school students.