Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study Gives Lowdown On High-Temperature Superconductivity

04.03.2004


A new study by theoretical physicists at the University of Toronto and the University of California at Los Angeles (ULCA) could bring scientists one step closer to the dream of a superconductor that functions at room temperature, rather than the frigid temperatures more commonly found in deep space.


Microscopic image of a ceramic superconductor
Image: Michael W. Davidson
Florida State University



The findings, which appear in the March 4 issue of the journal Nature, identify three factors that explain a perplexing pattern in the temperatures at which multi-layered ceramic materials become superconductors. The study could advance research in medical imaging, electrical power transmission and magnetically levitating trains. Its authors are U of T physics professor Hae-Young Kee and post-doctoral fellow Klaus Völker, and Professor Sudip Chakravarty of UCLA’s physics and astronomy department.

Superconductivity is a phenomenon that occurs when certain metals are cooled to near absolute zero, a temperature equivalent to zero degrees Kelvin (K), -273 C or -459 F. In ceramic materials, the phenomenon appears at about 100K. At a so-called critical temperature—that varies depending on the number of layers within the ceramic substance—the material becomes capable of conducting electricity without any energy loss.


Despite the value of such an efficient system, the supercooling—usually done with liquid nitrogen or liquid helium—makes superconductors impractical for many applications. “A room temperature superconductor would be a revolution, but even a superconductor with a higher critical temperature would have extremely important implications for multiple industries,” says Kee, who holds the Canada Research Chair in Theoretical Condensed Matter Physics.

Materials scientists have developed a group of “high-temperature” superconductors made with layers of copper oxides sandwiched between insulating filler material. This material reaches critical temperatures in the range of roughly 130K—the highest know critical temperatures to date. Previous studies on superconductors have established that while the critical temperature rises as the number of layers increase from one to three, it then drops off. By the time the number of layers rises to seven, the critical temperature has fallen below that of the single-layer superconductor.

Scientists have previously suggested that the critical temperature increase between one- and three-layered materials is due to the ability of electron pairs to tunnel between the layers of superconducting material.

Now, Kee and her colleagues have identified the factors that combine with a mechanism—known as the competing order—that lowers a superconductor’s critical temperature in materials with more than three layers. That “competing order,” in turn, is dependent on an uneven distribution of electrons, resulting in a charge imbalance between the material’s multiple layers. Kee and her colleagues are the first group to put these three factors—the tunnelling, the competing order and the charge imbalance—together.

“If we can find a way to affect the charge imbalance, we could suppress the competing order and develop superconducting materials with higher and higher critical temperatures,” says Kee. “And if you can push the superconducting temperature higher, then it will become much cheaper to apply this technology.”

The research was funded by the U.S. National Science Foundation, the Natural Sciences and Engineering Research Council of Canada, the Canadian Institute of Advanced Research, the Canada Research Chairs program and the Alfred P. Sloan Foundation.


CONTACT:

Klaus Völker
Department of Physics
416-333-5633 (cell)
voelker@physics.utoronto.ca

Hae-Young Kee (available March 4)
Department of Physics
416-978-5196
hykee@physics.utoronto.ca

Nicolle Wahl
U of T Public Affairs
416-978-6974
nicolle.wahl@utoronto.ca

Nicolle Wahl | University of Toronto
Further information:
http://www.utoronto.ca
http://www.newsandevents.utoronto.ca/bin5/040303b.asp

More articles from Physics and Astronomy:

nachricht New method gives microscope a boost in resolution
10.12.2018 | Rudolf-Virchow-Zentrum für Experimentelle Biomedizin der Universität Würzburg

nachricht A new 'spin' on kagome lattices
10.12.2018 | Boston College

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

Im Focus: Substitute for rare earth metal oxides

New Project SNAPSTER: Novel luminescent materials by encapsulating phosphorescent metal clusters with organic liquid crystals

Nowadays energy conversion in lighting and optoelectronic devices requires the use of rare earth oxides.

Im Focus: A bit of a stretch... material that thickens as it's pulled

Scientists have discovered the first synthetic material that becomes thicker - at the molecular level - as it is stretched.

Researchers led by Dr Devesh Mistry from the University of Leeds discovered a new non-porous material that has unique and inherent "auxetic" stretching...

Im Focus: The force of the vacuum

Scientists from the Theory Department of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science (CFEL) in Hamburg have shown through theoretical calculations and computer simulations that the force between electrons and lattice distortions in an atomically thin two-dimensional superconductor can be controlled with virtual photons. This could aid the development of new superconductors for energy-saving devices and many other technical applications.

The vacuum is not empty. It may sound like magic to laypeople but it has occupied physicists since the birth of quantum mechanics.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

Expert Panel on the Future of HPC in Engineering

03.12.2018 | Event News

 
Latest News

Small but ver­sat­ile; key play­ers in the mar­ine ni­tro­gen cycle can util­ize cy­anate and urea

10.12.2018 | Life Sciences

New method gives microscope a boost in resolution

10.12.2018 | Physics and Astronomy

Carnegie Mellon researchers probe hydrogen bonds using new technique

10.12.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>