Imaging Non-Local Magnetization Dynamics

Abstract

Many fundamental processes in magnetism take place on a nanometer length and sub-picosecond time scale. An important example of such phenomena in magnetism is ultrafast, spin-polarized transport of laser-excited hot electrons, which is now being recognized as playing a crucial role for novel spintronic devices and for optically induced magnetic switching. Recent experimental examples include the demonstration of all-optical helicity dependent control of spin-polarized currents at interfaces [1], the design of novel and efficient terahertz emitters [2], and nanoscale spin reversal in chemically heterogeneous GdFeCo driven by non-local transfer of angular momentum [3]. In particular, for advanced information technologies with bit densities already exceeding 1 terabit per square inch with bit cell dimensions of (15 × 38 nm²) [4], it is of fundamental importance to understand and eventually control the mechanisms responsible for optically induced spin dynamics on the nanoscale.

Acknowledgement

The authors gratefully acknowledge the staff of the different divisions of FERMI for their excellent support provided during preparation and realization of the experiments presented in this article.

Funding

The TU Berlin group acknowledges financial support received from the Helmholtz Virtual Institute “Dynamic Pathways in Multidimensional Landscapes” (VH-VI-419). Support from the CNRS through the PEPS SASELEX and from the French ANR via the UMAMI project is acknowledged by the French partners.