The research field of magnetic frustration is dominated by triangle-based lattices but exotic phenomena can also be observed in pentagonal networks, as the well-known Cairo lattice. We demonstrate it here with the prototypical Bi2Fe4O9 material. Thanks to a neutron scattering investigation, we unveil various facets of its unconventional magnetism, including a rationalization of its non-collinear magnetic order, exotic magnetic excitations, and dimer physics.
CEA is a French government-funded technological research organisation in four main areas: low-carbon energies, defense and security, information technologies and health technologies. A prominent player in the European Research Area, it is involved in setting up collaborative projects with many partners around the world.