Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ultra-Thin Nanowires Can Trap Electron ‘Twisters’ That Disrupt Superconductors

26.02.2015

Superconductor materials are prized for their ability to carry an electric current without resistance, but this valuable trait can be crippled or lost when electrons swirl into tiny tornado-like formations called vortices. These disruptive mini-twisters often form in the presence of magnetic fields, such as those produced by electric motors.

To keep supercurrents flowing at top speed, Johns Hopkins scientists have figured out how to constrain troublesome vortices by trapping them within extremely short, ultra-thin nanowires. Their discovery was reported Feb. 18 in the journal Physical Review Letters.


Nina Markovic and Tyler Morgan-Wall/jhu

This illustration depicts a short row of vortices held in place between the edges of a nanowire developed by Johns Hopkins scientists.

“We have found a way to control individual vortices to improve the performance of superconducting wires,” said Nina Markovic, an associate professor in the Department of Physics and Astronomy in the university’s Krieger School of Arts and Sciences.

Many materials can become superconducting when cooled to a temperature of nearly 460 below zero F, which is achieved by using liquid helium.

The new method of maintaining resistance-free current within these superconductors is important because these materials play a key role in devices such MRI medical scanners, particle accelerators, photon detectors and the radio frequency filters used in cell phone systems. In addition, superconductors are expected to become critical components in future quantum computers, which will be able to do more complex calculations than current machines.

Wider use of superconductors may hinge on stopping the nanoscopic mischief that electron vortices cause when they skitter from side to side across a conducting material, spoiling the zero-resistance current. The Johns Hopkins scientists say their nanowires keep this from happening.

Markovic, who supervised the development of these wires, said other researchers have tried to keep vortices from disrupting a supercurrent by “pinning” the twisters to impurities in the conducting material, which renders them unable to move.

“Edges can also pin the vortices, but it is more difficult to pin the vortices in the bulk middle area of the material, farther away from the edges,” she said. “To overcome this problem, we made a superconducting sample that consists mostly of edges: a very narrow aluminum nanowire.”

These nanowires, Markovic said, are flat strips about one-billionth as wide as a human hair and about 50 to 100 times longer than their width. Each nanowire forms a one-way highway that allows pairs of electrons to zip ahead at a supercurrent pace.

Vortices can form when a magnetic field is applied, but because of the material’s ultra-thin design, “only one short vortex row can fit within the nanowires,” Markovic said. “Because there is an edge on each side of them, the vortices are trapped in place and the supercurrent can just slip around them, maintaining the resistance-free speed.”

The ability to control the exact number of vortices in the nanowire may produce additional benefits, physics experts say. Future computers or other devices may someday use vortices instead of electrical charges to transmit information, they say.

The lead author of the Physical Review Letters article was Tyler Morgan-Wall, a doctoral student in Markovic’s lab. Along with Markovic, the co-authors were Benjamin Leith, who was an undergraduate at Johns Hopkins when the research took place; Nikolaus Hartman, a graduate student; and Atikur Rahman, who was a postdoctoral fellow in Markovic’s lab.

This research was support by National Science Foundation grants DMR-1106167 and PHYS-1066293. The Physical Review Letters journal article may be viewed at: http://journals.aps.org/prl/pdf/10.1103/PhysRevLett.114.077002 

Color illustration and photographs available; contact Phil Sneiderman

Contact Information
Phil Sneiderman
Office: 443-997-9907/Cell: 410-299-7462
prs@jhu.edu / On Twitter: @filroy

Phil Sneiderman | newswise

More articles from Physics and Astronomy:

nachricht NASA laser communications to provide Orion faster connections
30.03.2017 | NASA/Goddard Space Flight Center

nachricht Pinball at the atomic level
30.03.2017 | Max-Planck-Institut für Struktur und Dynamik der Materie

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

'On-off switch' brings researchers a step closer to potential HIV vaccine

30.03.2017 | Health and Medicine

Penn studies find promise for innovations in liquid biopsies

30.03.2017 | Health and Medicine

An LED-based device for imaging radiation induced skin damage

30.03.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>