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Magnetic Skyrmion Spin‐Torque Nano‐Oscillators
Author(s) -
Guslienko Konstantin Y.
Publication year - 2020
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.202000032
Subject(s) - skyrmion , nanopillar , condensed matter physics , physics , oscillation (cell signaling) , radius , current (fluid) , spin (aerodynamics) , perpendicular , vortex , mechanics , quantum mechanics , nanostructure , chemistry , geometry , thermodynamics , biochemistry , computer security , mathematics , computer science
The skyrmion oscillation frequency and steady orbit radius in ultrathin ferromagnetic layer of circular nanopillar are calculated in response to a spin‐polarized current. The analytical model of the rigid skyrmion motion is used. It is shown that the steady skyrmion oscillations with a frequency of about 1 GHz exist within finite range of the current. The case of the current perpendicular to the free layer plane and two types of the reference layer polarizations, uniform and vortex‐like, are considered. The first critical current can be very low in the case of zero difference between the skyrmion and vortex helicities. The second critical current is considered as a current of the skyrmion expelling from the free layer (dot). The oscillation frequency increases essentially with the current increasing. It is a function of the skyrmion equilibrium radius, dot radius, and the dot magnetic parameters.