Researchers at Florida State University have discovered a new way to improve the performance of electrical wires used as high temperature superconductors (HTS), findings that have the potential to power a new generation of particle accelerators.
An image of Bi-2212 bismuth-based superconducting wires. (Mark Wallheiser / FAMU-FSU College of Engineering) Researchers used high-resolution scanning electron microscopy to understand how processing methods influence grains in bismuth-based superconducting wires (known as Bi-2212) . These grains form the underlying structures of high-temperature superconductors, and scientists observing Bi-2212 grains at the atomic scale have successfully optimized their alignment in a process that makes the material more efficient at carrying superconducting current, or supercurrent. Their work has been published in the journal Superconductor science and technology.
The researchers found that the individual grains had a long rectangular shape, with their longer side pointing along the same axis as the wire – a so-called biaxial texture. They are arranged in a circular pattern following the path of the wire, so that the orientation is only apparent at a very small scale. These two properties together give the Bi-2212 grains a near biaxial texture, which has proven to be an ideal configuration for overcurrent flow.
“By understanding how to optimize the structure of these grains, we can fabricate the HTS round wires that carry higher currents in the most efficient way,” said Abiola Temidayo Oloye, a doctoral student at FAMU-FSU College of Engineering, researcher at the National High Magnetic Field Laboratory (MagLab) and lead author of the article.
Superconductors, unlike conventional conductors such as copper, can carry electricity with perfect efficiency because electrons do not encounter any friction as they move through the superconducting wire. Bi-2212 wires belong to a new generation of high field superconductors for the construction of superconducting magnets, which are crucial tools for scientific research in laboratories around the world, including the National High Magnetic Fields Laboratory where l he research team carried out its experiments.
High temperature superconductors like the Bi-2212 can conduct current at much higher magnetic fields than low temperature superconductors (LTS) and are a key part of the design of even more powerful particle accelerators at the Large Collider. hadrons from the European Organization for Nuclear Research. (CERN).
“We optimized the Bi-2212 round wires to carry more current, keeping in mind the difference in scale between the lab and the manufacturer,” Oloye said. “The process we are developing in the lab has to evolve at the manufacturing level for the technology to be commercially viable and we were able to do that in the study.
Previous work by Fumitake Kametani, Associate Professor of Mechanical Engineering at FAMU-FSU College of Engineering, MagLab Researcher and Principal Investigator for the study, showed the importance of quasi-biaxial texture in Bi-2212 round wires for currents. This article continued the premise and demonstrated the factors necessary to achieve optimal near-biaxial texture.
“The microstructural characterization used is unique in the analysis of the crystal structure of Bi-2212 round wires,” Kametani said. “The technique is typically used to analyze metals and alloys, and we have adapted it to develop new sample preparation methods to further optimize Bi-2212 HTS wire technologies.”
The overall goal is to be able to use Bi-2212 round wires in future high field magnet applications.
“Since this is the only high temperature superconductor available as a round wire, the material can more easily replace existing technologies by using LTS wires made from other materials,” said Oloye. “Other HTSs such as REBCO and Bi-2223 are only available in ribbon form, which adds a layer of complexity to the design of the magnets.”
Researchers from the National Laboratory for High Magnetic Fields at FSU and CERN headquarters contributed to this research.
The work was funded and supported by the US Department of Energy, the National Science Foundation, and the State of Florida.
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Material provided by Florida State University. Original written by Trisha Radulovich. Note: Content can be changed for style and length.