Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

ORNL paper examines clues for superconductivity in an iron-based material

06.05.2014

For the first time, scientists have a clearer understanding of how to control the appearance of a superconducting phase in a material, adding crucial fundamental knowledge and perhaps setting the stage for advances in the field of superconductivity.

The paper, published in Physical Review Letters, focuses on a calcium-iron-arsenide single crystal, which has structural, thermodynamic and transport properties that can be varied through carefully controlled synthesis, similar to the application of pressure. To make this discovery, researchers focused on how these changes alter the material’s Fermi surface, which maps the specific population and arrangement of electrons in materials.


A change of Hall and Seebeck effects point to large Fermi surface modification at the structural transition, preventing superconductivity at low temperatures. The change in the Fermi surface topology has been confirmed by angle-resolved photoemission spectroscopy.

“The Fermi surface is basically the ‘genetic code’ for causing a certain property, including superconductivity, in a material,” said Athena Safa-Sefat of the Department of Energy’s Oak Ridge National Laboratory, which led the research team.

“We can make different phases of this material in single crystal forms and measure their structure and properties, but now we have Fermi surface signatures that explain why we can't induce superconductivity in a certain structural phase of this material.”

Superconducting wires conduct electricity without resistance and could save the nation billions of dollars per year by virtually eliminating transmission losses on the grid, or they can be used to make compact, light and powerful motors and generators. This particular material is of special interest because it adds critical knowledge to the field of superconductivity that will ultimately allow such widespread applications.

The lead author of this paper, Krzysztof Gofryk, who did this work as a post-doctoral fellow at ORNL, showed how the interplay of structure and magnetism affected the Fermi surface and hence the electronic properties.

In calcium-iron-arsenide, the bulk superconducting state is absent because of the large Fermi surface modification at the structural transition.

This work represents a significant step forward for understanding this material's rich phase diagram and causes of superconductivity, Sefat said.
 
Other authors of the paper, titled “Fermi-Surface Reconstruction and Complex Phase Equilibria in CaFe2As2,” are ORNL’s post-doctoral fellow Bayrammurad Saparov and scientists from Los Alamos National Laboratory and Dresden University of Technology. The paper is available at http://arxiv.org/abs/1404.1095.

This research was funded by DOE’s Office of Science and by LANL’s Laboratory Directed Research and Development program.

UT-Battelle manages ORNL for the Department of Energy’s Office of Science. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of the time. For more information, please visit href="http://arxiv.org/abs/1404.1095".

Ron Walli | Eurek Alert!

Further reports about: Fermi Laboratory ORNL Office Superconducting pressure transition

More articles from Materials Sciences:

nachricht Electrifying Research: Piezoelectric Effects for the Suppression of Material Stresses
30.03.2015 | Austrian Science Fund FWF

nachricht Recipe for antibacterial plastic: Plastic plus egg whites
30.03.2015 | University of Georgia

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Experiment Provides the Best Look Yet at 'Warm Dense Matter' at Cores of Giant Planets

In an experiment at the Department of Energy's SLAC National Accelerator Laboratory, scientists precisely measured the temperature and structure of aluminum as...

Im Focus: Energy-autonomous and wireless monitoring protects marine gearboxes

The IPH presents a solution at HANNOVER MESSE 2015 to make ship traffic more reliable while decreasing the maintenance costs at the same time. In cooperation with project partners, the research institute from Hannover, Germany, has developed a sensor system which continuously monitors the condition of the marine gearbox, thus preventing breakdowns. Special feature: the monitoring system works wirelessly and energy-autonomously. The required electrical power is generated where it is needed – directly at the sensor.

As well as cars need to be certified regularly (in Germany by the TÜV – Technical Inspection Association), ships need to be inspected – if the powertrain stops...

Im Focus: 3-D satellite, GPS earthquake maps isolate impacts in real time

Method produced by UI researcher could improve reaction time to deadly, expensive quakes

When an earthquake hits, the faster first responders can get to an impacted area, the more likely infrastructure--and lives--can be saved.

Im Focus: Atlantic Ocean overturning found to slow down already today

The Atlantic overturning is one of Earth’s most important heat transport systems, pumping warm water northwards and cold water southwards. Also known as the Gulf Stream system, it is responsible for the mild climate in northwestern Europe. 

Scientists now found evidence for a slowdown of the overturning – multiple lines of observation suggest that in recent decades, the current system has been...

Im Focus: Robot inspects concrete garage floors and bridge roadways for damage

Because they are regularly subjected to heavy vehicle traffic, emissions, moisture and salt, above- and underground parking garages, as well as bridges, frequently experience large areas of corrosion. Most inspection systems to date have only been capable of inspecting smaller surface areas.

From April 13 to April 17 at the Hannover Messe (hall 2, exhibit booth C16), engineers from the Fraunhofer Institute for Nondestructive Testing IZFP will be...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

World Conference On Regenerative Medicine 2015: Registration And Abstract Submission Now Open

25.03.2015 | Event News

University presidents from all over the world meet in Hamburg

19.03.2015 | Event News

10. CeBiTec Symposium zum Big Data-Problem

17.03.2015 | Event News

 
Latest News

Researchers discover how body's good fat tissue communicates with brain

30.03.2015 | Life Sciences

For drivers with telescopic lenses, driving experience and training affect road test results

30.03.2015 | Health and Medicine

Climate change does not cause extreme winters

30.03.2015 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>