Researchers at NIST have discovered magnetic monopoles in a special type of magnetic material called “spin ice.” These monopoles are similar to the hypothetical magnetic particles theorized by Paul Dirac in 1931, but have never been observed before.
The spin ice material, made of dysprosium and titanium oxide, forms a unique crystalline structure where magnetic spins are arranged in a way that prevents them from forming a conventional magnetic order. Instead, the spins follow a “2-in & 2-out” pattern on each tetrahedron of the crystal lattice, creating a highly degenerate ground state.
Using neutron scattering experiments, researchers detected the presence of magnetic monopoles in this material. These monopoles are topological excitations that interact with each other through a magnetic Coulomb force, similar to how electric charges interact through the electric force.
The discovery of magnetic monopoles in a condensed matter system represents a new type of collective excitation and could lead to a better understanding of exotic quantum states of matter. This research also provides a new platform for studying the fundamental properties of magnetic monopoles and their interactions.
Source: https://www.nist.gov/ncnr/magnetic-monopoles-and-spin-liquids
Keywords: magnetic monopoles, spin ice, excitations
