Ultrafast dynamics of phonon-driven magnetization reversal at THz frequencies

The goal of this project will be to investigate ultrafast magnetization dynamics, with spatial and temporal resolution, via resonant excitation of optical phonons driven by THz pulses from the free electron laser FELIX. The questions of interactions between the crystal lattice and spin order are on foremost frontier of modern magnetism. Already in statics, crystalline order leads to fascinating types of magnetic order such as alteromagnets or spin density waves. Manipulating the lattice on ultrashort time scales one could achieve states of matter that are unthinkable otherwise. In addition to the free-electron laser, this research will use a number of synchronized femtosecond probe lasers, in various experimental conditions. This project is mostly experimental, but also requires good understanding of the magnetic interactions and ability to understand simple micromagnetic approaches. It will develop experimental techniques for single-shot detection of spatial and temporal dynamics of magnetic patterns excited with free-electron-laser pulses, and probed with table-top laser systems.