Pyrolytic Carbon - Magnetic Levitation

Magnetic Levitation

Few materials can be made to magnetically levitate stably above the magnetic field from a permanent magnet. Although magnetic repulsion is obviously and easily achieved between any two magnets, the shape of their field causes one to push the other off sideways, rather than supporting it stably above the other. Strongly diamagnetic materials though can be used for levitation above powerful magnets.

With the easy availability of rare earth permanent magnets in recent years, the strong diamagnetism of pyrolytic carbon makes it a convenient demonstration material for this effect.

A recent discovery in Japan shows that pyrolytic carbon can respond to laser light or sufficiently powerful natural sunlight by spinning or moving in the direction of the field gradient. The carbon's magnetic susceptibility changes upon illumination, leading to an unbalanced magnetization of the material and thus a sideways force.