  This study conducts a comprehensive investigation into the reversal mechanism
of magnetic vortex cores in a nanopillar system composed of two coupled
ferromagnetic dots under zero magnetic field conditions. The research employs a
combination of experimental and simulation methods to gain a deeper
understanding of the dynamics of magnetic vortex cores. The findings reveal
that by applying a constant direct current, the orientation of the vortex cores
can be manipulated, resulting in a switch in one of the dots at a specific
current value. The micromagnetic simulations provide evidence that this switch
is a consequence of a deformation in the vortex profile caused by the
increasing velocity of the vortex cores resulting from the constant amplitude
of the trajectory as frequency increases. These findings offer valuable new
insights into the coupled dynamics of magnetic vortex cores and demonstrate the
feasibility of manipulating their orientation using direct currents under zero
magnetic field conditions. The results of this study have potential
implications for the development of vortex-based non-volatile memory
technologies. \end{abstract}
