Designing a better superconductor with geometric frustration

Superconductors contain tiny tornadoes of supercurrent, called vortex filaments, that create resistance when they move. This affects the way superconductors carry a current.

But a magnet-controlled "switch" in superconductor configuration provides unprecedented flexibility in managing the location of vortex filaments, altering the properties of the superconductor, according to a new paper in Nature Nanotechnology.

"We work on superconductors and how to make them better for applications," said Boldizsár Jankó professor in the Department of Physics at the University of Notre Dame and co-corresponding author on the paper. "One of the major problems in superconductor technology is that most of them have these filaments, these tiny tornadoes of supercurrent.Whenthese move, then you have resistance."

Researchers have been trying to design new devices and new technologies to "pin," or fasten, these filaments to a specified position. Previous efforts to pin the filaments, such as irradiating or drilling holes in the superconductor, resulted in static, unchangeable arrays, or ordered arrangements of filaments. A new, dynamic system discovered by Jankó and collaborators will enable ongoing adjustments, altering the material's properties over time. The results of the research were published June 11 in Nature Nanotechnology in a paper titled "Switchable geometric frustration in an artificial-spin-ice/superconductor hetero-system."