Vortices and antivortices are typical non uniform magnetization configurations that can be achieved in spin-torque oscillators with in-plane materials. Dynamics of a vortex-antivortex pair, namely vortex dipole, were predicted and already observed. In this paper, we present a systematic micromagnetic study on that kind of dynamics in different spin-valves where the current is injected through a nano-aperture. Rotation and translation of vortex dipoles and rotation of vortex quadrupoles are shown depending on the shape and the size of the spin-valve. The origin of the different behaviors is explained within a micromagnetic framework.
@article{arxiv.1410.3957,
title = {Micromagnetic Study of Spin Transfer driven Vortex Dipole and Vortex Quadrupole Dynamics},
author = {A. Giordano and V. Puliafito and L. Torres and M. Carpentieri and B. Azzerboni and G. Finocchio},
journal= {arXiv preprint arXiv:1410.3957},
year = {2018}
}