Researchers peg magnetism as key driver of high-temperature superconductivity

July 5, 2006

When it comes to superconductivity, magnetic excitations may top good vibrations. Writing in the July 6, 2006, issue of Nature, scientists working at the Commerce Department's National Institute of Standards and Technology Center for Neutron Research in collaboration with physicists from the University of Tennessee and Oak Ridge National Laboratory report strong evidence that magnetic fluctuations are key to a universal mechanism for pairing electrons and enabling resistance-free passage of electric current in high-temperature superconductors.

An important missing piece in the puzzle of high-temperature superconductivity, the finding should boost efforts to develop a variety of useful technologies now considered impractical for conventional superconductors, which work at markedly lower temperatures. Examples include loss-free systems for storing and distributing electric energy, superconducting digital routers for high-speed communications, and more efficient generators and motors.

The team was led by Pengcheng Dai, a UT-ORNL joint professor.

"Our results unify understanding of the role of magnetism in high-temperature superconductivity and move the research community one step closer to understanding the underlying pairing mechanism itself," says NIST physicist Jeffrey Lynn, a member of the collaboration. Better understanding of the mechanism of high-temperature superconductivity may lead to the discovery of new materials in which electrical resistance vanishes at even warmer temperatures.

Objects of intense scientific and technological interest since their discovery in 1986, high-temperature superconductors work their magic in ways different than materials that become superconducting at significantly colder temperatures, as first observed in 1911. In these conventional superconductors, vibrations in the materials' atomic latticework mediate the pairing process that results in the unimpeded flow of electrons.

Scientists have ruled out vibrations, or phonons, as the likely electron matchmaker in high-temperature superconducting compounds. And while they have assembled important clues over the last two decades, researchers have yet to pin down the electron-pairing mechanism in the high-temperature superconductors.

"Various experiments and theories have suggested that this resonance--this sharp magnetic excitation--may be the glue needed to explain high-temperature superconductivity, but key pieces of evidence were missing," explains lead author Stephen Wilson, a UT graduate student.

Previous work by other researchers had determined that magnetism played a role in one of two major classes of high-temperature superconductors--those engineered with holes, or occasional vacancies where electrons normally would reside. But, until this work, carried out at NCNR and ORNL's High Flux Isotope Reactor, the underlying pairing mechanism in the other class--materials doped with an excess of electrons--eluded detection.

Using neutron probes, which are extremely sensitive to magnetism, the team was the first to observe a magnetic resonance in an electron-doped high-temperature superconductor, in a carefully engineered compound known as PLCCO. More importantly, the resonance energy was found to obey a well-established relationship universal to high-temperature superconductors, irrespective of type.

This demonstrated a fundamental link between magnetism and the superconducting phase, the researchers report. These observations and findings should open new avenues of research into the exotic properties of high-temperature superconductors, they write.

Source: National Institute of Standards and Technology

4.3 /5 (24 votes)  

Rank 4.3 /5 (24 votes)
Tags

Relevant PhysicsForums posts
  • gas leaks in space
    created2 hours ago
  • Weight required to balance a boom stand?
    created3 hours ago
  • Questions about Equivalence principle & Einstein Elevator?
    created5 hours ago
  • Kinetic energy of gas
    created6 hours ago
  • Understanding induced emfs
    created8 hours ago
  • What is the precise definition of a year?
    created9 hours ago
  • More from Physics Forums - General Physics

More news stories

Explained: Sigma

It's a question that arises with virtually every major new finding in science or medicine: What makes a result reliable enough to be taken seriously? The answer has to do with statistical significance -- but ...

Physics / General Physics

created Feb 09, 2012 | popularity 5 / 5 (19) | comments 66

Quantum physicist explains $100K offer for proof scaled-up quantum computing is impossible

(PhysOrg.com) -- MIT researcher Scott Aaronson has certainly riled the physics community with his offer this past Friday, of $100,000 to anyone who can prove that scaled-up quantum computing is impossible. ...

Physics / Quantum Physics

created Feb 08, 2012 | popularity 4.2 / 5 (13) | comments 35 | with audio podcast weblog

Diamond light, brighter than the sun

It’s the size of five football pitches and generates light 10 billion times brighter than the sun. As the Diamond Light Source celebrates its tenth anniversary this year, Penny Bailey visits one of the ...

Physics / General Physics

created Feb 07, 2012 | popularity 4.3 / 5 (7) | comments 18 | with audio podcast

Physicists 'record' magnetic breakthrough

An international team of scientists has demonstrated a revolutionary new way of magnetic recording which will allow information to be processed hundreds of times faster than by current hard drive technology.

Physics / General Physics

created Feb 07, 2012 | popularity 4.5 / 5 (41) | comments 14 | with audio podcast

Hints of the Higgs - papers are submitted

Back in December 2011, the ATLAS and CMS experiments at CERN presented some exciting results that provided tantalising hints of the Higgs boson.

Physics / General Physics

created Feb 08, 2012 | popularity 4.1 / 5 (7) | comments 10


Latin America mining boom clashes with conservation

Latin America is experiencing a mining boom as prices rise fuelled by a hike in global demand, but the region is also being hit by a wave of violent protests, strikes and rallies by environmentalists.

Love a click away in Indonesia's Twitter Republic

He was a geeky kid from Yogyakarta, she a glamorous city girl in Jakarta. In a country with one of the world's most vibrant social networking scenes they fell in love on Twitter.

Walney offshore wind farm is world's biggest (for now)

(PhysOrg.com) -- The Walney wind farm on the Irish Sea--characterized by high tides, waves and windy weather--officially opened this week. The farm is treated in the press as a very big deal as the Walney ...

GPS court ruling leaves US phone tracking unclear

A US Supreme Court decision requiring a warrant to place a GPS device on the car of a criminal suspect leaves unresolved the bigger issue of police tracking using mobile phones, legal experts say.

Europeans protest controversial Internet pact

Tens of thousands of people marched in protests in more than a dozen European cities Saturday against a controversial anti-online piracy pact that critics say could curtail Internet freedom.

Europe stakes billion-dollar bet on new rocket

A pencil-slim rocket is scheduled to lift into space from South America on Monday, carrying a billion-dollar bet that Europe can grab a juicy slice of the market to place satellites in low orbit.