Frequency generation by a magnetic vortex-antivortex dipole in spin-polarized current
Department of Applied Mathematics, University of Crete - 71409 Heraklion, Crete, Greece, EU
Accepted: 11 May 2012
We study the dynamics of a vortex-antivortex (VA) dipole which may be generated due to spin-polarized current flowing through a magnetic element. We employ the Landau-Lifshitz equation with a Slonczewski spin-torque term with in-plane polarization. We establish that the vortex dipole is set in steady-state rotational motion. The frequency of rotation is due to two independent forces: the interaction between the two vortices and an external in-plane magnetic field. The nonzero skyrmion number of the dipole is responsible for both forces giving rise to rotational dynamics. The spin torque acts to stabilize the rotational motion. We give analytical and numerical results for the frequency of rotation and VA dipole features as functions of the parameters.
PACS: 75.78.-n – Magnetization dynamics / 75.70.Kw – Domain structure (including magnetic bubbles and vortices) / 75.78.Fg – Dynamics of domain structures
© EPLA, 2012