Learn more physics!
I have been unable to find this question answered and you guys have the most user friendly website I have found. My questions is:
What materials would prevent two magnets from attracting to each other when placed between them?
Melbourne, Victoria, Australia
Magnetic fields don't penetrate type I superconductors, so a big sheet
of one of them would work. Of course it would have to be kept cold, and
if the fields are too big it just quits superconducting.
Highly magnetizable material (mu-metal) can also work, if it's
arranged in the right geometry. Mu-metal does the opposite of the
superconductor. It pulls magnetic field lines in, rather than expelling
them. A loop of mu-metal from one pole to the other of one of the
magnets would keep that magnet's field from extending out as much as it
normally would. Of course, a strip of mumetal from one magnet toward
the other magnet can actually increase the attraction.
(published on 10/22/2007)
Follow-up on this answer.