The Meissner
effect in superconductors like this black ceramic yttrium
based superconductor acts to exclude magnetic fields from the
material. Since the electrical resistance is zero, supercurrents are
generated in the material to exclude the magnetic fields from a
magnet brought near it. The currents which cancel the external field
produce magnetic poles which mirror the poles of the permanent
magnet, repelling them to provide the lift to levitate
the magnet.
The levitation process is quite remarkable. Since the levitating
currents in the superconductor meet no resistance, they can adjust
almost instantly to maintain the levitation. The suspended magnet
can be moved, put into oscillation, or even spun rapidly and the
levitation currents will adjust to keep it in suspension.
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