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Communications and External Relations
Audio Spot: New superconductor receives ORNL neutron analysis
OAK RIDGE, Tenn.,
June 4, 2008
Researchers at Oak Ridge National Laboratory's High Flux Isotope Reactor (HFIR), a Department of Energy neutron science facility, have analyzed a newly discovered material with superconducting properties at relatively high temperatures.
The experiments with one of the HFIR's triple-axis spectrometers are among a flurry of activities that follow the February announcement of the iron-based superconducting compound by Japanese researchers. It is the first such class of materials to be identified in more than two decades.
The finding may provide researchers with new clues to how high-temperature superconductors are able to conduct electricity with no resistance, something that has baffled scientists for two decades.
Practical applications of high-temperature superconducting (HTS) materials would alleviate a host of energy-related issues, including power transmission and transportation.
A team of researchers from ORNL, the University of Tennessee and the National Institutes of Technology, led by ORNL and UT researcher Pengcheng Dai, published a paper in Nature on May 28 describing experiments that appear to support the theory that a very subtle magnetism is responsible for the HTS effect.
"Neutron scattering is the only probe that can tell you the magnetic structure as well as the magnetic moment size. That's where our contributions come in, in determining the electronic state of the material," Dai said.
With the newly refurbished HFIR and the Spallation Neutron Source (SNS), also at ORNL, ramping up to full power, neutron scientists will likely be lining up with experiments to solve the HTS riddle.
When completed, the SNS will have 24 neutron scattering instruments and the HFIR will have 15. The SNS-HFIR combination will make ORNL the world's foremost center for materials research with neutrons.
Dai noted that opposing theories have attributed HTS properties to either some force of magnetism that overcomes the electrons' mutual repulsion or something almost magical about cuprates.
"The cuprate superconductors until now have been the only ones known at high temperatures. From this perspective, finding another example of a high-temperature superconductor which does not contain copper but also has magnetism is extremely important, and that's where our work lies," he said.
ORNL is managed by UT-Battelle for the Department of Energy.