With the development of pump-probe techniques by means of pulsed laser systems, it has become feasible to initiate ultrafast magnetization phenomena optically and to observe them on a subpicosecond timescale. In this work, time-resolved measurements of magnetization precession in epitaxial ferromagnetic films grown on GaAs single crystal substrates were performed. The presented results focus on the characteristics of the precession frequency, phase, decay time and amplitude as a function of an externally applied magnetic field.
Furthermore, two-dimensional snap-shots are shown which visualize the dynamics and reveal the relation between the phase- and amplitude characteristics and magnetization reversal. Finally, computational methods were used in order to obtain the magnetic anisotropy constants from fitting eigenfrequencies calculated on the basis of a theoretical model to experimentally observed eigenfrequencies.