Physicists from the UK and France have developed a new approach to inducing magnetic charges to flow in tiny crystals using short magnetic-field pulses, in a similar way to electrical charges flowing through batteries and biological systems. They have created an environment where long-lived currents of magnetic monopoles can be created and manipulated through applying magnetic fields in spin ice, a crystalline material, in what is termed ‘magnetricity’.

The study, published in Nature Physics [Giblin et al. Nature Physics (2011) doi: 10.1038/nphys1896], revealed that the magnetic molecules in spin ice are unlike those in normal magnets, which always consist of dipoles. In spin ice they are arranged in triangular pyramids that stop them from being able to line up easily with all their poles pointing in the same direction. The researchers showed that a molecule will occasionally squirm and flip over, creating two separate poles, with the actual molecule remaining where it was. The new poles are able to move about independently of each other while continuing chain reactions from the flipping molecules move them on from one pyramid to another.

Once the poles have moved far enough away from the original molecule, they start to lose all memory of each other, and the dipole becomes split in two, creating two monopoles. Although monopoles are more commonly associated with magnetic charges inside a vacuum, in spin ice the poles behave similarly, with each having a magnetic charge that interacts with each other in the same way as electric charges.