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Magnetic flux pinning sometimes there and sometimes not.

  1. Oct 22, 2013 #1
    Hello. As far as I know about superconductors, if you put a superconducting material in a magnetic field and then cool that material below its critical temperature, the material should lock to that magnetic field (magnetic flux pinning). Now I have seen videos where the locked magnet/material is pushed away but it bounces back to its locked state (like here ).

    Now there is another video where the material gets pushed away and re-locks in a different position (). My question is, why in the latter video the superconducting disc did not stay in its original position and allowed itself to be locked in a new one numerous times? I apologize for the mistakes I made in terminology and English.
    Last edited by a moderator: Sep 25, 2014
  2. jcsd
  3. Oct 23, 2013 #2


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    The flux pinning occurs along defects, impurties etc. where the flux "sticks"; if you apply enough force you can move the flux (i.e. the vortices) around and then it will stick in a new configuration.
    It is also possible to have multiple stable configurations.

    Am "ideal" type II superconductor made from a perfect crystal would behave differently.
  4. Oct 23, 2013 #3
    Thank you.
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