• About
    • About Us
    • What We Cover
  • Advertise
    • Advertise
    • Our Advertisers
  • Contact
  • Donate
  • Send News

Oak Ridge Today

  • Home
  • Sign in
  • News
    • Business
    • Community
    • Education
    • Government
    • Health
    • Police and Fire
    • U.S. Department of Energy
    • Weather
  • Sports
    • High School
    • Middle School
    • Recreation
    • Rowing
    • Youth
  • Entertainment
    • Arts
    • Dancing
    • Movies
    • Music
    • Television
    • Theater
  • Premium Content
  • Obituaries
  • Classifieds

ORNL scientists uncover clues to role of magnetism in iron-based superconductors

Posted at 1:12 am August 25, 2014
By Oak Ridge National Laboratory Leave a Comment

Magnetism of Iron-based Superconductors

Oak Ridge National Laboratory scientists used scanning transmission electron microscopy to measure atomic-scale magnetic behavior in several families of iron-based superconductors. (Photo courtesy ORNL)

 

New measurements of atomic-scale magnetic behavior in iron-based superconductors by researchers at Oak Ridge National Laboratory and Vanderbilt University are challenging conventional wisdom about superconductivity and magnetism.

The study published in Advanced Materials provides experimental evidence that local magnetic fluctuations can influence the performance of iron-based superconductors, which transmit electric current without resistance at relatively high temperatures.

“In the past, everyone thought that magnetism and superconductivity could not coexist,” said ORNL’s Claudia Cantoni, the study’s first author. “The whole idea of superconductors is that they expel magnetic fields. But in reality things are more complicated.”

Superconductivity is strongly suppressed by the presence of long-range magnetism—where atoms align their magnetic moments over large volumes—but the ORNL study suggests that rapid fluctuations of local magnetic moments have a different effect. Not only does localized magnetism exist, but it is also correlated with a high critical temperature, the point at which the material becomes superconducting. [Read more…]

Filed Under: Front Page News, Oak Ridge National Laboratory, Science, U.S. Department of Energy Tagged With: Advanced Materials, Andrew May, Athena Safa-Sefat, atomic-scale magnetic behavior, Brian Sales, Center for Nanophase Materials Sciences, Claudia Cantoni, DOE, Elbio Dagotto, electric current, electron energy loss spectroscopy, iron-based superconductors, Jonathan Mitchell, Juan-Carlos Idrobo, magnetic moments, magnetic properties, magnetism, Matthew Chisholm, Michael McGuire, National Science Foundation, Oak Ridge National Laboratory, Office of Science, Orbital occupancy and charge doping in iron-based superconductors, ORNL, scanning transmission electron microscopy, superconductivity, superconductors, Tom Berlijn, U.S. Department of Energy, University of Tennessee Stephen Pennycook, Vanderbilt University, Wu Zhou

Five ORNL scientists rated among world’s most influential

Posted at 12:33 pm August 1, 2014
By Oak Ridge National Laboratory Leave a Comment

Ramamoorthy Ramesh

Ramamoorthy Ramesh

Five Oak Ridge National Laboratory physicists, including Deputy for Science and Technology Ramamoorthy Ramesh, have been named by Thomson Reuters as some of the best and brightest of our time.

The list consists of scientists whose work has been most frequently cited by peers as identified by Thomson Reuters platforms. Citation data was divided into two categories—2002-2012 and 2012-2013—with the latter labeled “hot papers,” ranking in the top 0.1 percent by citations in their field. Seventeen researchers earned this distinction while some 3,200 were included in the second section of the ranking with citations ranking in the top 1 percent for their field and year of publication.

Ramesh, who was actually listed in two categories—physics and materials science—was named to his position at ORNL in June 2013 after serving as the Plato Malozemoff Chair Professor of Materials Science and Engineering and Physics at the University of California, Berkeley, with a joint appointment as a faculty senior scientist at Lawrence Berkeley National Laboratory. He holds a doctorate in materials science from the University of California, Berkeley, and was elected to the National Academy of Engineering in 2011 in recognition of his contributions to the science and technology of functional complex oxide materials. [Read more…]

Filed Under: Oak Ridge National Laboratory, ORNL, Science, Slider, Top Stories, U.S. Department of Energy Tagged With: Athena Safa-Sefat, Brian Sales, chemistry, citations, condensed matter physics, crystallographic studies, David Singh, distinguished scientists, electronic materials, Eugene Wigner Fellow, magnetic materials, materials science, Michael McGuire, Oak Ridge National Laboratory, ORNL, ORNL Directors Award, ORNL scientists, physical property measurements, physicists, physics, R&D 100, Ramamoorthy Ramesh, rare-earth materials, scientists, solid-state chemistry, solid-state chemistry and metallurgical synthesis techniques, Thomson Reuters

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

Posted at 11:52 am May 30, 2014
By Oak Ridge National Laboratory Leave a Comment

FERMI Figure

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. (Image courtesy ORNL)

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.

“The Fermi surface is basically the ‘genetic code’ for causing a certain property, including superconductivity, in a material,” said Athena Safa-Sefat of the U.S. 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.” [Read more…]

Filed Under: Front Page News, Oak Ridge National Laboratory, U.S. Department of Energy Tagged With: Athena Safa-Sefat, Bayrammurad Saparov, calcium-iron-arsenide single crystal, Dresden University of Technology, Fermi surface, Fermi-Surface Reconstruction and Complex Phase Equilibria in CaFe2As2, Krzysztof Gofryk, Laboratory Directed Research and Development, LANL, Los Alamos National Laboratory, Oak Ridge National Laboratory, Office of Science, ORNL, Physical Review Letters, superconducting, superconductivity

ORNL study advances quest for better superconducting materials

Posted at 11:36 pm January 28, 2014
By Oak Ridge National Laboratory Leave a Comment

Superconductivity Pan Defects

Minghu Pan’s image of “clover-like” atomic defects—an example is circled—that result in strong superconductivity. (Photo courtesy ORNL)

Nearly 30 years after the discovery of high-temperature superconductivity, many questions remain, but an Oak Ridge National Laboratory team is providing insight that could lead to better superconductors.

Their work, published in Physical Review Letters, examines the role of chemical dopants, which are essential to creating high-temperature superconductors—materials that conduct electricity without resistance. The role of dopants in superconductors is particularly mysterious as they introduce non-uniformity and disorder into the crystal structure, which increases resistivity in non-superconducting materials.

By gaining a better understanding of how and why chemical dopants alter the behavior of the original (parent) material, scientists believe they can design superconductors that work at higher temperatures. This would make them more practical for real-world wire applications because it would lessen the extreme cooling required for conventional superconducting material. Existing “high-temperature superconductors” operate at temperatures in the range of negative 135 degrees Celsius and below. [Read more…]

Filed Under: Front Page News, Oak Ridge National Laboratory, Science, U.S. Department of Energy Tagged With: Athena Safa-Sefat, atomic defect, Bayrammurad Saparov, chemical dopants, Claudia Cantoni, crystal, DOE, DOE Information Center, dopants, high-temperature superconductivity, high-temperature superconductors, Jonathan Mitchell, Krzysztof Gofryk, Local inhomogeneity and filamentary superconductivity in Pr-doped CaFe2As2, Materials Science and Technology Division, Minghu Pan, Oak Ridge National Laboratory, ORNL, Physical Review Letters, superconductors, U.S. Department of Energy

Search Oak Ridge Today

Classifieds

Availability of the draft environmental assessment for off-site depleted uranium manufacturing (DOE/EA-2252)

The U.S. Department of Energy (DOE) National Nuclear Security Administration (NNSA) announces the … [Read More...]

Public Notice: NNSA announces no significant impact of Y-12 Development Organization operations at Horizon Center

AVAILABILITY OF THE FINAL ENVIRONMENTAL ASSESSMENT FOR THE OFFSITE HOUSING OF THE Y-12 DEVELOPMENT … [Read More...]

ADFAC seeks contractors for five homes

Aid to Distressed Families of Appalachian Counties (ADFAC) is a non-profit community based agency, … [Read More...]

Recent Posts

  • Flatwater Tales Storytelling Festival Announces 2025 Storytellers
  • Laser-Engraved Bricks Will Line Walkway of New Chamber Headquarters
  • Democratic Women’s Club to Discuss Climate Change, Energy and Policy
  • Estate Jewelry Show at Karen’s Jewelers Features Celebrity Jewelry
  • Keri Cagle named new ORAU senior vice president and ORISE director
  • ORAU Annual Giving Campaign exceeds $100,000 goal+ORAU Annual Giving Campaign exceeds $100,000 goal More than $1 million raised in past 10 years benefits United Way and Community Shares Oak Ridge, Tenn. —ORAU exceeded its goal of raising $100,000 in donations as part of its internal annual giving campaign that benefits the United Way and Community Shares nonprofit organizations. ORAU has raised more than $1 million over the past 10 years through this campaign. A total of $126,839 was pledged during the 2024 ORAU Annual Giving Campaign. Employees donate via payroll deduction and could earmark their donation for United Way, Community Shares or both. “ORAU has remained a strong pillar in the community for more than 75 years, and we encourage our employees to consider participating in our annual giving campaign each year to help our less fortunate neighbors in need,” said ORAU President and CEO Andy Page. “Each one of our employees has the power to positively impact the lives of those who need help in the communities where we do business across the country and demonstrate the ORAU way – taking care of each other.” ORAU, a 501(c)(3) nonprofit corporation, provides science, health and workforce solutions that address national priorities and serve the public interest. Through our specialized teams of experts and access to a consortium of more than 150 major Ph.D.-granting institutions, ORAU works with federal, state, local and commercial customers to provide innovative scientific and technical solutions and help advance their missions. ORAU manages the Oak Ridge Institute for Science and Education (ORISE) for the U.S. Department of Energy (DOE). Learn more about ORAU at www.orau.org. Learn more about ORAU at www.orau.org. Like us on Facebook: https://www.facebook.com/OakRidgeAssociatedUniversities Follow us on X (formerly Twitter): https://twitter.com/orau Follow us on LinkedIn: https://www.linkedin.com/company/orau ###
  • Children’s Museum Gala Celebrates the Rainforest
  • Jim Sears joins ORAU as senior vice president
  • Oak Ridge Housing Authority Receives Funding Assistance of up to $51.8 Million For Renovating Public Housing and Building New Workforce Housing
  • Two fires reported early Friday

Recent Comments

  • Raymond Mitchell on City manager’s ‘State of the City’ canceled due to weather
  • Raymond Mitchell on City manager’s ‘State of the City’ canceled due to weather
  • Mysti M Desilva on Crews clearing roads, repairing water line breaks
  • Mel Schuster on Crews clearing roads, repairing water line breaks
  • Cecil King on Crews clearing roads, repairing water line breaks
  • Rick Morrow on Roads, schools, businesses closed after heavy snow
  • Diana lively on Free community Thanksgiving Dinner on Nov. 25
  • Anne Garcia on School bus driver arrested following alleged assault on elementary student
  • Raymond Dickover on Blockhouse Valley Recycling Center now open 6 days per week
  • Mike Mahathy on School bus driver arrested following alleged assault on elementary student

Copyright © 2025 Oak Ridge Today