Friday, November 15, 2013

The Levitate the Magnet Trick circa 1960

This one of the more interesting magnet levitating over a superconductor pictures I've seen in a while.  The sequence shows a magnet on the end of a non-ferromagnetic chain being lowered into a superconducting dish.  The chain becomes a graphically impressive part of the demo in the last frame.  You might have heard that magnets won't levitate stably over a flat type I superconductor, and the won't.  The sides of the dish are adding lateral repulsive forces that keep the magnet in place!
The picture is from "Cryophysics" by K. Mendelssohn.  It's volume 7 of the excellent and completely out of print "Interscience Tracts on Physics and Astronomy"

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