  A magnetic vortex is a curling magnetic structure realized in a ferromagnetic
disk, which is a promising candidate of a memory cell for future nonvolatile
data storage devices. Thus, understanding of the stability and dynamical
behaviour of the magnetic vortex is a major requirement for developing magnetic
data storage technology. Since the experimental proof of the existence of a
nanometre-scale core with out-of-plane magnetisation in the magnetic vortex,
the dynamics of a vortex has been investigated intensively. However, the way to
electrically control the core magnetisation, which is a key for constructing a
vortex core memory, has been lacking. Here, we demonstrate the electrical
switching of the core magnetisation by utilizing the current-driven resonant
dynamics of the vortex; the core switching is triggered by a strong dynamic
field which is produced locally by a rotational core motion at a high speed of
several hundred m/s. Efficient switching of the vortex core without magnetic
field application is achieved thanks to resonance. This opens up the
potentiality of a simple magnetic disk as a building block for spintronic
devices like a memory cell where the bit data is stored as the direction of the
nanometre-scale core magnetisation.
