Mr Goodnight

A Magnet with “One Pole”

While a magnetic monopole particle has never been conclusively observed, there are a number of phenomena in condensed-matter physics where a material, due to the collective behavior of its electrons and ions, can show emergent phenomena that resemble magnetic monopoles in some respect. These should not be confused with actual monopole particles: since all known particles have zero magnetic charge (including the protons, neutrons, and electrons that make up the whole periodic table), it is fundamentally impossible to find a true magnetic monopole in ordinary matter made from atoms; only quasiparticles are possible. In particular, the law ∇⋅B=0 is true everywhere in these systems, which it would not be in the presence of a true magnetic monopole particle. The Dirac string model describes such a system in the theoretical limit of infinitely thin connecting fluxtubes.

http://en.wikipedia.org/wiki/Magnetic_monopole