Femtosecond Magnetooptics and the Orbital Model of the Ultrafast Magnetic Dynamics

The critical analysis of the magnetization reversal processes and magnetooptics of ferromagnets was carried out. The condition of the formation of nonequilibrium orbital momenta lpf after turning off the femtosecond laser pumping was found. The frequency range for processes involving lpf was estimated as 106 Hz to 1015 Hz. Such objects were not known in the magnetism before using the methods of femtosecond optics. The estimated frequency range covers all the processes related to femtosecond magnetism. Our qualitative analysis of these processes allows us to hope that their quantitative description does not require significant changes in the existing theories of magnetism.