Applied Superconductivity Center Research
The Applied Superconductivity Center focuses its research in the areas listed below. Click on the topic links for more details, or read up on some of the recent research in these areas highlighted below.
BSCCO, the leading high temperature superconductor with Tc of 110K, has been demonstrated to be the most technically viable present materials for superconducting application to electric power transmission lines, fault current limiters, transformers, electromagnets and motors.
We address the key underlying scientific and engineering issues of YBa2Cu3O7-x Coated Conductors (CCs). We characterize forefront samples using magneto-optical imaging, SEM, and Jc(H) measurements for the purpose of understanding and resolving key performance issues. Areas of concentration for us include substrates, buffer layers, the superconducting over layer and their complex interactions. CCs are polycrystalline by nature, consisting of multiple GBs and intragrain regions, and we also seek to understand the consequences of this granularity.
Our underlying goal is to understand "real" grain boundaries (GBs) of high Tc superconductors in all their multi-scale complexity. This requires a forefront, mix of sample design and fabrication, film growth, superconducting property characterization, nanoscale microstructure and electronic structure determination, methods to modify GB properties and theory that takes full account of the complex materials science of these materials.
Low Temperature Superconductivity (LTS) typically refers to the Nb-based alloy (most commonly Nb-47wt.%Ti) and A15 (Nb3Sn and Nb3Al) superconductors in use prior to the discovery of "high temperature" oxide superconductors in 1986. "Temperature" here refers to the temperature below which the superconductor must be cooled in order for it to become superconducting. For LTS superconductors that temperature is usually well below 20 K (-253 °C).
In January 2001, a totally new superconductor was discovered, with a surprising critical temperature of 39 K - MgB2. This discovery stimulated a global flurry of work seeking higher Tc and uncovering the basic physics. Although so far higher Tc has not been found, we now know that MgB2 is akin to other LTS intermetallics, with high Tc coming from the exceptionally high vibrational energies in the graphite-like boron planes. Thus, MgB2 appears to obey conventional models of superconductivity, and this more simple view (as compared to HTS) opens up a wide range of practical opportunities.
A coordinated, multi-institutional research proposal that addresses the key underlying scientific and engineering issues of Generation II Coated Conductors based on YBa2Cu3Ox (or alternatives such as YBa2Cu4O8, Tl2Ba2CaCu3Ox, or HgBa2CaCu2Ox) superconductor is described. The research is funded by the Air Force Office of Scientific Research / Multidisciplinary Research Program (AFOSR MURI).