Resilient Bi-2212 Round Wire

Published October 25, 2021

Inverse pole figure maps (IPF) of a longitudinal cross section of an individual Bi-2212 filament in the highest Jc sample. The dominance of green indicates a strong a-axis alignment.

Researchers studied the mechanics of supercurrent flow in state-of-the-art Bi-2212 superconducting round wires and learned that the microstructure of the superconducting filaments is inherently resilient, work that could open the door to new opportunities to raise supercurrent capacity of Bi-2212 round wires.

What is the finding?

To understand the mechanics of Bi-2212 (Bi₂Sr₂Ca₁Cu₂O_x) superconducting round wires with the goal of optimizing its performance, we studied the property changes after removing oxygen from optimized, oxygen overdoped Bi-2212 round wires. We found that although removing oxygen from Bi-2212 round wires decreased their performance, our samples did not develop significant supercurrent bottlenecks, indicating that the microstructure of the superconducting filaments is inherently very resilient against the formation of weak links, a situation unique to Bi-2212 among high-temperature superconductors.

Why is this important?

These results bring the high-temperature superconducting (HTS) materials community closer to realizing and controlling high performance in Bi-2212 round wires. Improved performance is likely to lead to a new frontier of high-field magnets that use Bi-2212 round wire. Round wire is typically easier to form into cables that are necessary to wind low-inductance, hence better-protected HTS magnets. Round wires might also enable higher-homogeneity HTS magnets.

Who did the research?

Y. Oz^1,2, J. Jiang², M. Matras^2,3, T.A. Oloye^2,3, F. Kametani^2,3, E.E. Hellstrom^2,3, D.C. Larbalestier^2,3

¹Florida State University, ²Applied Superconductivity Center, ³FAMU-FSU College of Engineering

Why did this research need the MagLab?

A wide and diverse array of electromagnetic characterization devices were used by researchers at the MagLab's Applied Superconductivity Center, including magnetometers, magnets, and electron microscopes. This research infrastructure, along with the unique skills of the interdisciplinary research team, made possible this study of the conductor and its applications in test coils.

Details for scientists

View or download the expert-level Science Highlight, Absence of Weak-Links in Bi-2212 Round Wire
Read the full-length publication, Conundrum of strongly coupled supercurrent flow in both under- and overdoped Bi-2212 round wires, in Phys. Rev. Materials

Funding

This research was funded by the following grants: NSF DMR-1644779; DMR-1157490; DE-SC0010421

For more information, contact Lance Cooley.

Tools They Used

This research was conducted in the Helios G4 Scanning Electron Microscope, 5T SQUID, 14T Vibrating Sample Magnetometer, 15T Superconducting Magnet at the MagLab's Applied Superconductivity Center