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I Impact of superconductivity on mechanical properties?

  1. Feb 13, 2019 at 2:23 PM #1

    fluidistic

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    It is often said that the mechanical properties of metals are mostly due to their free electrons. I'm talking about malleability, ductility and hardness.
    So, when they suffer a superconductive transition, I expect a drastic change in their mechanical properties, but I haven't found anything on the Internet about such consequences.

    My questions are: What can we expect, regarding the mechanical properties of metals, when they pass from a non superconducting state to a superconducting state?

    What about type II superconductors?
     
  2. jcsd
  3. Feb 15, 2019 at 2:46 PM #2
    Not all electrons are involved within the superconducting phase - only those within a gap about the Fermi surface.

    The thermal and electronic properties of the material would change, but why do you think the mechanical properties would change drastically at all?
     
  4. Feb 15, 2019 at 3:11 PM #3

    fluidistic

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    For the exact same reason their thermal and electronic properties would change.
     
  5. Feb 15, 2019 at 3:35 PM #4

    ZapperZ

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    Who said that?

    Zz.
     
  6. Feb 16, 2019 at 7:41 AM #5

    fluidistic

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    Starting with Ron Maimon:
    Following by socratic.org:
    Lastly, Wikipedia:
    So I would expect that if a "condensation" of the electrons near the Fermi surface occur, like in a superconductivity transition, the mechanical properties I've mentioned in my first post would drastically change.
     
  7. Feb 16, 2019 at 5:16 PM #6

    king vitamin

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    The solution is basically what entr0pic said: only a small fraction of electrons undergo Cooper pairing. In particular, only the electrons within about a Debye energy of the Fermi surface pair up. A typical Fermi energy of a metal is on the order of 1-10 eV, while the typical Debye energy is .01 eV, so typically less than 1 out of every 100 electrons "localizes" into a Cooper pair (though Cooper pairs are fairly delocalized themselves relative to the typical microscopic length scales).
     
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