  The bistability of the core magnetization of nano-scaled magnets with a
magnetic vortex configuration has great potential for data storage
applications. To exploit this, reliable switching between the two possible
states is needed. Time resolved x-ray microscopy was used to study the response
of the vortex core to excitation pulses at sub-ns timescales and image the
vortex core switching. A reliable switching process by coherent excitation with
leading and trailing edges of in-plane magnetic field pulses was found and
compared with micromagnetic simulations.
