Magnetic monopoles could rewrite what we know about magnets and could find applications in the computer industry.
Magnets have both a north and south pole, as every school child is taught in science class. If you take a magnet and break it in half, you are left with two magnets, each having a north and south pole.
Researchers from Germany have just created the first artificial magnetic monopoles, which have either a north or south pole, but not both. No natural material ever discovered has this characteristic.
The monopoles were crreated from merging skyrmions, which are small whirlpools of magnetic force in material consisting of iron, cobalt and silicon. Although the fields created are not true magnetic fields, they do affect the passage of electrons in the same way that magnets fields do, and so physicists describe these whirlpools as artificial magnetic fields.
The monopole created is similar to a subatomic particle first proposed in 1931 by the physicist Paul Dirac. This particle would be able to explain why protons and electrons have the exact same amount of charge, despite being fundamentally different particles in nearly every other way. This newly-discovered phenomenon only happens within materials known as chiral magnets.
Lukas Eng from the Technischen Universität in Dresden and his team made careful observations of these magnetic whirls using a magnetic force microscope. They found that as the skyrmions break apart, they merge with one another. In Munich, meanwhile, Christian Pfleiderer was studying the scattering of neutrons in the same materials, and concluded that the process of skyrmions merging was also occurring in his experiments. Computer simulations conducted in Cologne by Stefan Buhrandt and Christoph Schutte, working under Achim Rosch, determined that this merging was happening not only on the surface, but within the material itself. As two swirls begin to merge together, there is a point in the material where they meet up.
"This means that an artificial magnetic monopole has to sit on this point. [W]henever two magnetic whirls merge in the experiment, an artificial magnetic monopole has flown through surface," Rosch said.
Dirac's particle was theorized to give all elementary particles a quantized charge. No matter what particle we are looking at, argued Dirac, the charge should be equal to a fundamental charge, multiplied by a whole number.
"It is fascinating that something as fundamental as a magnetic monopole can be realized in a piece of material," Buhrandt said.
Strangely, though, these newly-discovered monopoles affect eelctrons, but not protons. This one feature of the newly-found monopoles does not match up with what Dirac predicted 82 years ago.
The findings were presented in the journal Science.
