Electromagnetic Imaging of Vortex Dynamics in High-Temperature Superconductors

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This individual investigator award is to several professors at the University of Rochester for a project aimed at an improved understanding of the vortex dynamics and pinning effects in high-temperature superconductors (HTS). This project will make use of modern femtosecond laser techniques and both electro-optic (EO) and magneto-optic (MO) imaging methods to provide time-resolved two-dimensional images of intrinsic vortex dynamics in HTS thin films, single crystals, and wires. Specific problems to be addressed include vortex nucleation and motion in the presence of random and periodic pinning, dynamical phase transitions of vortex matter induced by transport current, and vortex velocity distributions in flux-flow channels above the critical current. This research should have important implications for high-power applications of HTS materials. This is a highly interdisciplinary research project, which will involve graduate and undergraduate students and faculty members in physics, materials science, and electrical and computer engineering at the University of Rochester, as well as researchers at Argonne National Laboratory. The students will gain skills to enable them to compete in the future market place.%%%Superconductors are of great importance because they can carry very large electrical currents with zero resistance. These currents in turn produce very large magnetic fields. However, for currents above a certain "critical current", the material will no longer be a superconductor since magnetic vortices suddenly penetrate the superconductor, producing resistive loss and sometimes catastrophic heating in the material. In order to make superconductors that can carry ever higher currents, it is essential to understand this breakdown mechanism in more detail. This individual investigator award is to several professors at the University of Rochester for a project that will make use of femtosecond lasers arranged as ultrafast two-dimensional imaging cameras to take a series of snapshots of a superconductor while this breakdown is taking place, resulting in a "slow-motion movie" of the rapid dynamics of the magnetic vortices as they enter the superconductor. The results of this study should provide clues to making higher-quality High-temperature superconducting wires, tapes, and thin films for a variety of electronic and energy-related applications. This is a highly interdisciplinary research project, which will involve graduate and undergraduate students and faculty members in physics, materials science, and electrical and computer engineering at the University of Rochester, as well as researchers at Argonne National Laboratory. The students will gain skills to enable them to compete in the future market place.***