© NISTMagnetic monopoles are created when the spin of an ion in one corner of a spin ice crystal is knocked askew, creating a monopole (red sphere) and adjacent antimonopole (blue sphere)
In 1931, Paul Dirac, one of the rock stars of the physics world, made the somewhat startling prediction that "magnetic monopoles," or particles possessing only a single pole - either north or south - should exist. His conclusion stemmed from examining a famous set of equations that explains the relationship between electricity and magnetism. Maxwell's equations apply to long-known electric monopole particles, such as negatively charged electrons and positively charged protons; but despite Dirac's prediction, no one has found magnetic monopole particles.
Now, a research team working at NIST's Center for Neutron Research (NCNR), led by Hiroaki Kadowaki of Tokyo Metropolitan University, has found the next best thing. By creating a compound that under certain conditions forms large, molecule-sized monopoles that behave exactly as the predicted particles should, the team has found a way to explore magnetic monopoles in the laboratory, not just on the chalkboard. (Another research team, working simultaneously, published similar findings in Science last month.)
