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arXiv · 1806.06585

Current-driven domain wall motion along ferromagnetic strips with periodically-modulated perpendicular anisotropy

Luis Sánchez-Tejerina·Óscar Alejos·Víctor Raposo·Eduardo Martínez
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Abstract

The dynamics of magnetic domain walls along ferromagnetic strips with spatially modulated perpendicular magnetic anisotropy is theoretically studied by means of micromagnetic simulations. Ferromagnetic layers with a periodic sawtooth profile of the anisotropy depict a well-defined set of energy minima where the walls are pinned in the absence of external stimuli, and favor the unidirectional propagation of domain walls. The performance of the current-driven domain wall motion along these ratchet-like systems is compared to the field-driven case. Our study indicates that the current-driven domain wall motion exhibits significant improvements with respect to the field-driven case in terms of bit shifting speed and storage density, and therefore, it is suggested for the development of novel devices. The feasibility of these current-driven ratchet devices is studied by means of realistic micromagnetic simulations and supported by a one-dimensional model updated to take into account the periodic sawthooth anisotropy profile. Finally, the current-driven domain wall motion is also evaluated in systems with a triangular modulation of the anisotropy designed to promote the bidirectional shifting of series of walls, a functionality that cannot be achieved by magnetic fields.

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Luis Sánchez-Tejerina, Óscar Alejos, Víctor Raposo, Eduardo Martínez. 2018-06-18. Current-driven domain wall motion along ferromagnetic strips with periodically-modulated perpendicular anisotropy. https://doi.org/10.1063/1.5036601

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