Coherent radiation by magnets with exchange interactions

A wide class of materials acquire magnetic properties due to particle interactions through exchange forces. These can be atoms and molecules composing the system itself, as in the case of numerous magnetic substances. Or these could be different defects, as in the case of graphene, graphite, carbon nanotubes, and related materials. A theory is suggested describing a fast magnetization reversal in magnetic systems, whose magnetism is caused by exchange interactions. The effect is based on the coupling of a magnetic sample with an electric circuit producing a feedback magnetic field. This method can find various applications in spintronics. The magnetization reversal can be self-organized, producing spin superradiance. A part of radiation is absorbed by a resonator magnetic coil. But an essential part of radiation can also be emitted through the coil sides. (paper)