Nanotechnology Now





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > The Quest for a New Class of Superconductors

This photo shows a magnet levitating above a high-temperature superconductor, cooled with liquid nitrogen. A persistent electric current flows on the surface of the superconductor, effectively forming an electromagnet that repels the magnet. The expulsion of an electric field from a superconductor is known as the \"Meissner Effect.\"
This photo shows a magnet levitating above a high-temperature superconductor, cooled with liquid nitrogen. A persistent electric current flows on the surface of the superconductor, effectively forming an electromagnet that repels the magnet. The expulsion of an electric field from a superconductor is known as the \"Meissner Effect.\"

Abstract:
Possibilities abound 50 years after theory of superconductivity

The Quest for a New Class of Superconductors

LOS ALAMOS, NM | Posted on December 22nd, 2007

Fifty years after the Nobel-prize winning explanation of how superconductors work, a research team from Los Alamos National Laboratory, the University of Edinburgh, and Cambridge University are suggesting another mechanism for the still-mysterious phenomenon.

In a review published today in Nature, researchers David Pines, Philippe Monthoux and Gilbert Lonzarich posit that superconductivity in certain materials can be achieved absent the interaction of electrons with vibrational motion of a material's structure.

The review, "Superconductivity without phonons," explores how materials, under certain conditions, can become superconductors in a non-traditional way. Superconductivity is a phenomenon by which materials conduct electricity without resistance, usually at extremely cold temperatures around minus 424 degrees Fahrenheit (minus 253 degrees Celsius)-the fantastically frigid point at which hydrogen becomes a liquid. Superconductivity was first discovered in 1911.

A newer class of materials that become superconductors at temperatures closer to the temperature of liquid nitrogen-minus 321 degrees Fahrenheit (minus 196 degrees Celsius)-are known as "high-temperature superconductors."

A theory for conventional low-temperature superconductors that was based on an effective attractive interaction between electrons was developed in 1957 by John Bardeen, Leon Cooper and John Schrieffer. The explanation, often called the BCS Theory, earned the trio the Nobel Prize in Physics in 1972.

The net attraction between electrons, which formed the basis for the BCS theory, comes from their coupling to phonons, the quantized vibrations of the crystal lattice of a superconducting material; this coupling leads to the formation of a macroscopically occupied quantum state containing pairs of electrons-a state that can flow without encountering any resistance, that is, a superconducting state.

"Much like the vibrations in a water bed that eventually compel the occupants to move together in the center, phonons can compel electrons of opposite spin to attract one another, says Pines, who with Bardeen in 1954, showed that this attraction could win out over the apparently much stronger repulsion between electrons, paving the way for the BCS theory developed a few years later.

However, according to Pines, Monthoux and Lonzarich, electron attraction leading to superconductivity can occur without phonons in materials that are on the verge of exhibiting magnetic order-in which electrons align themselves in a regular pattern of alternating spins.

In their Review, Pines, Monthoux and Lonzarich examine the material characteristics that make possible a large effective attraction that originates in the coupling of a given electron to the internal magnetic fields produced by the other electrons in the material. The resulting magnetic electron pairing can give rise to superconductivity, sometimes at substantially higher temperatures than are found in the materials for which phonons provide the pairing glue.

Among the classes of materials that appear capable of superconductivity without phonons are the so-called heavy electron superconductors that have been studied extensively at Los Alamos since the early 1980's, certain organic materials, and the copper oxide materials that superconduct at up to twice the temperature at which nitrogen liquefies.

"If we ever find a material that superconducts at room temperature-the 'Holy Grail' of superconductivity-it will be within this class of materials," says Pines. "This research shows you the lamp post under which to look for new classes of superconducting materials."

Pines is the founder and Co-Director of the University of California's Institute for Complex Adaptive Matter, founded at Los Alamos in 1999, and a staff member of Los Alamos' Materials Physics and Applications Division. Monthoux is part of Edinburgh University's Centre for Science at Extreme Conditions. Lonzarich is at the Cavendish Laboratory of the University of Cambridge. The trio began work on the review when Pines was on leave from Los Alamos at Cambridge in 2000.

####

About Los Alamos National Laboratory
Los Alamos National Laboratory is a multidisciplinary research institution engaged in strategic science on behalf of national security. The Laboratory is operated by a team composed of Bechtel National, the University of California, BWX Technologies, and Washington Group International for the Department of Energy's National Nuclear Security Administration.

Los Alamos enhances national security by ensuring the safety and reliability of the U.S. nuclear stockpile, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to energy, environment, infrastructure, health and global security concerns.

For more information, please click here

Contacts:
James E. Rickman

(505) 665-9203

Copyright © Los Alamos 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

Conversion of Greenhouse Gases to Syngas in Presence of Nanocatalysts in Iran May 22nd, 2015

New Antibacterial Wound Dressing in Iran Can Display Replacement Time May 22nd, 2015

Haydale Named Lead Sponsor for Cambridge Graphene Festival May 22nd, 2015

Simulations predict flat liquid May 21st, 2015

Discoveries

Conversion of Greenhouse Gases to Syngas in Presence of Nanocatalysts in Iran May 22nd, 2015

New Antibacterial Wound Dressing in Iran Can Display Replacement Time May 22nd, 2015

Nanotherapy effective in mice with multiple myeloma May 21st, 2015

Turn that defect upside down: Twin boundaries in lithium-ion batteries May 21st, 2015

Announcements

Conversion of Greenhouse Gases to Syngas in Presence of Nanocatalysts in Iran May 22nd, 2015

New Antibacterial Wound Dressing in Iran Can Display Replacement Time May 22nd, 2015

Haydale Named Lead Sponsor for Cambridge Graphene Festival May 22nd, 2015

INSIDDE: Uncovering the real history of art using a graphene scanner May 21st, 2015

Research partnerships

Supercomputer unlocks secrets of plant cells to pave the way for more resilient crops: IBM partners with University of Melbourne and UQ May 21st, 2015

Taking control of light emission: Researchers find a way of tuning light waves by pairing 2 exotic 2-D materials May 20th, 2015

Efficiency record for black silicon solar cells jumps to 22.1 percent: Aalto University's researchers improved their previous record by over 3 absolute percents in cooperation with Universitat Politècnica de Catalunya May 18th, 2015

Organic nanoparticles, more lethal to tumors: Carbon-based nanoparticles could be used to sensitize cancerous tumors to proton radiotherapy and induce more focused destruction of cancer cells, a new study shows May 18th, 2015

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