By: Yu Gaididei
From: Bogolyubov Institute for Theoretical Physics
At: Instituto de Investigação Interdisciplinar, Anfiteatro
Multivortex periodic structures in driven magnetic nanodots are studied. Spin-polarized current induced vortex lattices are investigated in the frame of Slonczewski-Berger mechanism. The existence of a critical currentÂ jcÂ which separates two regimes:
(i) deformed immobile vortex state,
(ii) vortex-antivortex periodic structures,
is shown. When jc â€¹ jc1 â€¹ j â€¹ j0, where j0 is the saturation current, periodic vortex-antivortex lattice appears. The lattice is stable for disturbances and rotates as a whole around the disk center. For currentsÂ in the interval jc â€¹ j â€¹ Jc1Â stable regular vortex-antivortex structures with symmetries C2, C3, C4 appear. The ring-type structures which are the circularly closed cross-tie domain walls are also observed in this regime. The mechanism of the vortex-antivortex lattice creation is discussed.