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Multivortex periodic structures in driven magnetic nanodots

By: Yu Gaididei
From: Bogolyubov Institute for Theoretical Physics
At: Instituto de Investigação Interdisciplinar, Anfiteatro
[2012-12-04] 14:00

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 current  jc  which separates two regimes:
(i) deformed immobile vortex state,
(ii) vortex-antivortex periodic structures,
is shown. When jc ‹ jc1 ‹ j ‹ 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 currents  in the interval jc ‹ j ‹ Jc1  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.