Resonant X-ray Diffraction and an X-ray viewpoint on All-Optical Switching

Laser-induced magnetization dynamics is a continuing puzzle in modern condensed matter physics. Exactly how does magnetization respond to a short laser pulse, in timescales ranging from less than 100 fs to a few picoseconds. Such laser pulses are observed to rapidly create non-equilibrium magnetic disorder and even allow new pathways to other magnetic states. The fundamental length scale relevant for these transformations is the exchange length – which sets how quickly magnetization can vary within a material. This is on the scale of a few nanometers in most magnetic materials. Resonant x-ray diffraction is becoming an important tool in exploring such magnetism dynamics at these nanometer length-, and subpicosceond time scales. In particular, we apply this technique to study the phenomena of all-optical magnetic switching in GdFeCo and TbFeCo and review the progress to understanding and controlling this process.