Magnetic counterparts to electric charges and currents have proved elusive. However, it was recently proposed that magnetic charges can exist in a certain type of material termed 'spin ice'. Here, experimental measurements prove that magnetic charges can indeed exist in such a material and have measurable currents, thus establishing an instance of perfect symmetry between electricity and magnetism.
- S. T. Bramwell
- S. R. Giblin
- T. Fennell
