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Stanford Researchers Discover a New Phase of Matter

By - Source: Stanford University | B 3 comments

They discovered that a type of high-temperature superconductor may feature a previously unknown phase of matter that could either work in favor of superconductivity or against it.

Superconductors are usually used in scientific experiments, for example by particle accelerators such as the Tevatron at Fermilab or the LHC at CERN. To reach superconductivity, superconductors are often cooled to absolute zero, which typically requires liquid helium as a coolant. Even high-temperature superconductors need to be cooled halfway to zero. Prior to entering the superconducting phase,  electrons are in an energy gap that arises when electrons pair off and drop to the lower energy level, which is the foundation for superconductivity. As soon as the temperature rises, the electrons split up, regain their previous energy level again and a material cannot superconduct anymore as a result.

Stanford's findings suggest that there is another phase in their copper-based superconductor: Many electrons do not pair off, but form an "elusive order" that had not been observed in the past. The researchers said that this state is not understood yet, but further research will highlight whether this phase works in favor of superconductivity or against it. If it is in favor, it can be promoted. If it is against it, it could be suppressed. In the next step, the researchers want to learn to understand the "nature" of this new phase.

The detailed research is published in the March 25 issue of Science.         

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    blubbey , 26 March 2011 14:38
    I don't mean to be a douche but this isn't correct -
    'To reach superconductivity, superconductors are often cooled to absolute zero'
    Afaik, nothing has been cooled to absolute zero, just very close. If it has, my mistake.
  • 1 Hide
    Anonymous , 26 March 2011 19:43
    @blubbey I think they meant "to absolute zero" as in towards AZ and to temperatures close to it, not AZ itself, we haven't witnessed anything hit it yet. Maybe dodgy wording, but I think it was more meant as they cool it to a target of AZ.
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    DouglasYBCO , 28 March 2011 09:11
    Low-temp superconductors are only superconducting below a critical temperature usually in the single digits of Kelvin. So you need liquid Helium at 4K to keep it that cold! The high-temperature superconductors can use liquid Nitrogen as a cryogen because their critical temperatures are above 77K. It's never really this simple with superconductors as it also depends greatly on their shape and the magnetic field it's in but that's more for Science than Tom's.

    We can't reach zero Kelvin... but we've cooled things down to nano-Kelvin.