The fundamental interactions and excitations governing magnetism and correlated matter occur on nanometer length-scales and femtosecond time-scales. Examples are phonons, magnons and electrons as well as their mutual interactions. A direct and selective excitation of these quasiparticles is possible with electromagnetic pulses at THz frequencies, whereas space-, element- and spin-resolved probing is provided by X-rays. Combining these two techniques will allow us to explore magnetic materials with unprecedented temporal, spatial and elemental resolution and to obtain quasiparticle-specific information, these being the key ingredients for understanding ultrafast magnetic phenomena.
Here, I will review the latest developments in our projects on ultrafast magnetism using both X-rays and THz radiation with a focus on magnetization switching phenomena.