If a metallic ferromagnet is excited with an ultrashort light pulse, its magnetization changes on femtosecond timescales. This discovery sparked the field of spintronics with envisioned applications ranging from faster memory devices to novel computation concepts for efficient information technology.

Even decades after the first experimental demonstration of ultrafast magnetization dynamics, some of the underlying mechanisms are still not fully understood, and regularly new phenomena are discovered. Therefore, we develop models to describe the magnetization dynamics on various levels ranging from phenomenological temperature-based models to full microscopic Boltzmann collision integrals. We evaluate the interplay of various interaction channels such as spin-dependent electron-electron and electron-phonon scattering to determine their effects on the magnetization dynamics.

If the ferromagnet is part of a multilayer, additional energy and particle transfer processes such as spin currents come into play, that can sometimes dominate the intrinsic processes. Thus, they provide an additional degree of freedom to control the magnetization dynamics. Systematically varying sample parameters such as the thickness of the individual layers allows to optimize optical manipulation of the magnetization. Our projects are closely related to complementary experiments, where we aim to aid in the interpretation of experimental results in order to identify the underlying physical mechanisms.