Nanoscale ultrafast magnetization behavior: from solitons to domain-wall displacement

Ultrafast magnetization switching has made it possible to envision new techniques for information storage at sub-nanosecond timescales. By switching, it is typically understood that a large spatial region of the magnetic material reverses its orientation, traditionally detected by spatially averaged measurements such as x-ray magnetic circular dichroism. However, access to time-dependent scattered x-rays revealed richer dynamics occurring at the nanoscale. In this talk, I will discuss advances in the analysis of x-ray scattering data to uncover nucleation of solitons and ultrafast domain perturbations. These dynamics entail both atomic and long-range interactions that represent a formidable yet interesting multiscale modeling problem. A new pseudo-spectral magnetization dynamics model provides promising results that could hold the key to achieving seamless multiscaling between atomistic spin dynamics and micromagnetic simulations.