January 30, 2016

First self-assembled superconductor structure created

Lindsay France/University Photography
Group leader Ulrich Wiesner, right, the Spencer T. Olin Professor of Engineering,
and graduate student and co-lead author Peter Beaucage, second from right, hold models
of the self-assembled gyroid superconductor the group created. Also pictured are
Bruce van Dover, left, professor in the Department of Materials Science and Engineering,
and Sol Gruner, the John L. Wetherill Professor of Physics.

(January 30, 2016)  Building on nearly two decades’ worth of research, a multidisciplinary team at Cornell has blazed a new trail by creating a self-assembled, three-dimensional gyroidal superconductor.

Ulrich Wiesner, the Spencer T. Olin Professor of Engineering, led the group, which included researchers in engineering, chemistry and physics.

The group’s findings are detailed in a paper published in Science Advances, Jan. 29.

Wiesner said it’s the first time a superconductor, in this case niobium nitride (NbN), has self-assembled into a porous, 3-D gyroidal structure. The gyroid is a complex cubic structure based on a surface that divides space into two separate volumes that are interpenetrating and contain various spirals. Pores and the superconducting material have structural dimensions of only around 10 nanometers, which could lead to entirely novel property profiles of superconductors.

Superconductivity for practical uses, such as in magnetic resonance imaging (MRI) scanners and fusion reactors, is only possible at near absolute zero (-459.67 degrees below zero), although recent experimentation has yielded superconducting at a comparatively balmy 94 degrees below zero.

“There’s this effort in research to get superconducting at higher temperatures, so that you don’t have to cool anymore,” Wiesner said. “That would revolutionize everything. There’s a huge impetus to get that.”

Superconductivity, in which electrons flow without resistance and the resultant energy-sapping heat, is still an expensive proposition. MRIs use superconducting magnets, but the magnets constantly have to be cooled, usually with a combination of liquid helium and nitrogen.

journal reference (pdf) >>