Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Argonne scientists discover new phase in iron-based superconductors

A team of scientists from Argonne National Laboratory discovered a new magnetic phase in iron-based superconductors. From left: Duck-Young Chung, Omar Chmaissem, Stephan Rosenkranz, Daniel Bugaris, Mercouri Kanatzidis, Ray Osborn and Jared Allred. Credit: Photo by Mark Lopez / Argonne National Laboratory.
A team of scientists from Argonne National Laboratory discovered a new magnetic phase in iron-based superconductors. From left: Duck-Young Chung, Omar Chmaissem, Stephan Rosenkranz, Daniel Bugaris, Mercouri Kanatzidis, Ray Osborn and Jared Allred.

Credit: Photo by Mark Lopez / Argonne National Laboratory.

Abstract:
Scientists at the U.S. Department of Energy's Argonne National Laboratory have discovered a previously unknown phase in a class of superconductors called iron arsenides. This sheds light on a debate over the interactions between atoms and electrons that are responsible for their unusual superconductivity.

Argonne scientists discover new phase in iron-based superconductors

Argonne, IL | Posted on May 23rd, 2014

"This new magnetic phase, which has never been observed before, could have significant implications for our understanding of unconventional superconductivity," said Ray Osborn, an Argonne physicist and coauthor on the paper.

Scientists and engineers are fascinated with superconductors because they are capable of carrying electric current without any resistance. This is unique among all conductors: even good ones, like the copper wires used in most power cords, lose energy along the way.

Why don't we use superconductors for every power line in the country, then? Their biggest drawback is that they must be cooled to very, very cold temperatures to work. Also, we do not fully understand how the newest types, called unconventional superconductors, work. Researchers hope that by figuring out the theory behind these superconductors, we could raise the temperature at which they work and harness their power for a wide range of new technologies.

The theory behind older, "conventional" superconductors is fairly well understood. Pairs of electrons, which normally repel each other, instead bind together by distorting the atoms around them and help each other travel through the metal. (In a plain old conductor, these electrons bounce off the atoms, producing heat). In "unconventional" superconductors, the electrons still form pairs, but we don't know what binds them together.

Superconductors are notably finicky; in order to get to the superconducting phase—where electricity flows freely—they need a lot of coddling. The iron arsenides the researchers studied are normally magnetic, but as you add sodium to the mix, the magnetism is suppressed and the materials eventually become superconducting below roughly -400 degrees Fahrenheit.

Magnetic order also affects the atomic structure. At room temperature, the iron atoms sit on a square lattice, which has four-fold symmetry, but when cooled below the magnetic transition temperature, they distort to form a rectangular lattice, with only two-fold symmetry. This is sometimes called "nematic order." It was thought that this nematic order persists until the material becomes superconducting—until this result.

The Argonne team discovered a phase where the material returns to four-fold symmetry, rather than two-fold, close to the onset of superconductivity. (See diagram).

"It is visible using neutron powder diffraction, which is exquisitely sensitive, but which you can only perform at this resolution in a very few places in the world," Osborn said. Neutron powder diffraction reveals both the locations of the atoms and the directions of their microscopic magnetic moments.

The reason why the discovery of the new phase is interesting is that it may help to resolve a long-standing debate about the origin of nematic order. Theorists have been arguing whether it is caused by magnetism or by orbital ordering.

The orbital explanation posits that electrons like to sit in particular d orbitals, driving the lattice into the nematic phase. Magnetic models, on the other hand (developed by study co-authors Ilya Eremin and Andrey Chubukov at the Institut für Theoretische Physik in Germany and the University of Wisconsin-Madison, respectively) suggest that magnetic interactions are what drive the two-fold symmetry—and that they are the key to the superconductivity itself. Perhaps what binds the pairs of electrons together in iron arsenide superconductors is magnetism.

"Orbital theories do not predict a return to four-fold symmetry at this point," Osborn said, "but magnetic models do."

"So far, this effect has only been observed experimentally in these sodium-doped compounds," he said, "but we believe it provides evidence for a magnetic explanation of nematic order in the iron arsenides in general."

It could also affect our understanding of superconductivity in other types of superconductors, such as the copper oxides, where nematic distortions have also been seen, Osborn said.

The paper, titled "Magnetically driven suppression of nematic order in an iron-based superconductor," was published today in Nature Communications.

Other coauthors on the paper were Argonne scientists Sevda Avci (now at Afyon Kocatepe University in Turkey), Omar Chmaissem (a joint appointment with Northern Illinois University), Jared M. Allred, Stephan Rosenkranz, Daniel Bugaris, Duck Young Chung, John-Paul Castellan, John Schlueter, Helmut Claus and Mercouri Kanatzidis (a joint appointment with Northwestern University); and Dmitry Khalyavin, Pascal Manuel and Aziz Daoud-Aladine at the ISIS Pulsed Neutron and Muon Source at the Rutherford Appleton Laboratory in Oxfordshire, U.K.

Funding for the research was provided by the U.S. Department of Energy's Office of Science. The neutron powder diffraction was performed at ISIS.

####

About DOE/Argonne National Laboratory
Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. 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 our time. For more information, visit science.energy.gov.

For more information, please click here

Contacts:
Jared Sagoff

630-252-5549

Louise Lerner

(630) 252-5526

Copyright © DOE/Argonne National Laboratory

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Chains of nanogold – forged with atomic precision September 23rd, 2016

Tattoo therapy could ease chronic disease: Rice-made nanoparticles tested at Baylor College of Medicine may help control autoimmune diseases September 23rd, 2016

Nanotech Grants Options September 22nd, 2016

Coffee-infused foam removes lead from contaminated water September 21st, 2016

Laboratories

NIST Patents Single-Photon Detector for Potential Encryption and Sensing Apps September 16th, 2016

Electron beam microscope directly writes nanoscale features in liquid with metal ink September 16th, 2016

World's most powerful X-ray takes a 'sledgehammer' to molecules September 14th, 2016

NIST illuminates transfer of nanoscale motion through microscale machine September 14th, 2016

Superconductivity

Subatomic microscopy key to building new classes of materials September 1st, 2016

Unraveling the crystal structure of a -70° Celsius superconductor, a world first: Significant advancement in the realization of room-temperature superconductors August 25th, 2016

Superconductivity: After the scenario, the staging August 20th, 2016

Superconductivity: After the scenario, the staging August 20th, 2016

Govt.-Legislation/Regulation/Funding/Policy

Tattoo therapy could ease chronic disease: Rice-made nanoparticles tested at Baylor College of Medicine may help control autoimmune diseases September 23rd, 2016

PHENOMEN is a FET-Open Research Project aiming to lay the foundations a new information technology September 19th, 2016

NIST Patents Single-Photon Detector for Potential Encryption and Sensing Apps September 16th, 2016

Electron beam microscope directly writes nanoscale features in liquid with metal ink September 16th, 2016

Discoveries

Chains of nanogold – forged with atomic precision September 23rd, 2016

Tattoo therapy could ease chronic disease: Rice-made nanoparticles tested at Baylor College of Medicine may help control autoimmune diseases September 23rd, 2016

Speedy bacteria detector could help prevent foodborne illnesses September 21st, 2016

Coffee-infused foam removes lead from contaminated water September 21st, 2016

Materials/Metamaterials

Chains of nanogold – forged with atomic precision September 23rd, 2016

Coffee-infused foam removes lead from contaminated water September 21st, 2016

Containing our 'electromagnetic pollution': MXene can protect mobile devices from electromagnetic interference September 13th, 2016

New material to revolutionize water proofing September 12th, 2016

Announcements

Chains of nanogold – forged with atomic precision September 23rd, 2016

Tattoo therapy could ease chronic disease: Rice-made nanoparticles tested at Baylor College of Medicine may help control autoimmune diseases September 23rd, 2016

Nanotech Grants Options September 22nd, 2016

Coffee-infused foam removes lead from contaminated water September 21st, 2016

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Chains of nanogold – forged with atomic precision September 23rd, 2016

Tattoo therapy could ease chronic disease: Rice-made nanoparticles tested at Baylor College of Medicine may help control autoimmune diseases September 23rd, 2016

Speedy bacteria detector could help prevent foodborne illnesses September 21st, 2016

Coffee-infused foam removes lead from contaminated water September 21st, 2016

Research partnerships

Tattoo therapy could ease chronic disease: Rice-made nanoparticles tested at Baylor College of Medicine may help control autoimmune diseases September 23rd, 2016

Graphene nanoribbons show promise for healing spinal injuries: Rice University scientists develop Texas-PEG to help knit severed, damaged spinal cords September 19th, 2016

NIST Patents Single-Photon Detector for Potential Encryption and Sensing Apps September 16th, 2016

Semiconducting inorganic double helix: New flexible semiconductor for electronics, solar technology and photo catalysis September 15th, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic