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Supercooled magnet- effects on other materials?

  1. May 31, 2006 #1
    If I were to take a permanent magnet and hold a piece of, say iron, a fixed distance away there would be constant attractive force generated between the two bodies. If I were then to cool the magnet down towards absolute zero, but keep the temperature of the iron constant, what changes would I expect to see in the force between the two materials?

    Does anyone know of this experiment being performed? If so, what were the results?

    Any information would be much appreciated.

    Oh, and “hi” to all on these forums, this is my first post!.
  2. jcsd
  3. May 31, 2006 #2


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    Nothing spectacular. The force will increase slowly as you cool the magnet. At about liquid helium, you may have an increase in the force of about* 20% compared to the room temperature
    value. If you heat it above room temperature, the force will decrease slowly until a certain temerature (called the Curie temperature), beyond which it falls rapidly and becomes vanishingly small.

    Yes, this experiment has been performed on thousands of different magnetic materials. Here's an example for one such :

    * Note : The actual value of how much it changes depends on the material that makes up the magnet. For an NdFeB magnet, I don't believe it increases by my than 10 or 20%. There are other materials where the increase may be as high as 100%, but these materials don't usually make great magnets at room temperature.
    Last edited: May 31, 2006
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