Domain-Wall Pinning by Local Control of Anisotropy in Pt/Co/Pt strips

Abstract

We theoretically and experimentally analyze the pinning of a magnetic domain wall (DW) at engineered anisotropy variations in Pt/Co/Pt strips with perpendicular magnetic anisotropy. An analytical model is derived showing that a step in the anisotropy acts as an energy barrier for the DW. Quantitative measurements are performed showing that the anisotropy can be controlled by focused ion beam irradiation with Ga ions. This tool is used to experimentally study the field-induced switching of nanostrips which are locally irradiated. The boundary of the irradiated area indeed acts as a pinning barrier for the domain wall and the pinning strength increases with the anisotropy difference. Varying the thickness of the Co layer provides an additional way to tune the anisotropy, and it is shown that a thinner Co layer gives a higher starting anisotropy thereby allowing tunable DW pinning in a wider range of fields. Finally, we demonstrate that not only the anisotropy itself, but also the width of the anisotropy barrier can be tuned on the length scale of the domain wall.

Published in Journal of Physics: Condensed Matter (special issue on Domain wall dynamics in nanostructures) 19 pages, 8 figures

References in corpus (3)

• Creep and flow regimes of magnetic domain wall motion in ultrathin Pt/Co/Pt films with perpendicular anisotropy
• High domain wall velocities induced by current in ultrathin Pt/Co/AlOx wires with perpendicular magnetic anisotropy
• Electric Control of Multiple Domain Walls in Pt/Co/Pt Nanotrack with Perpendicular Magnetic Anisotropy

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• Strength and length-scale of the interaction between domain walls and pinning disorder in thin ferromagnetic films
• Chiral magnetoresistance in Pt/Co/Pt zigzag wires
• Controlling Domain-Wall Nucleation in Ta/CoFeB/MgO Nanomagnets via Local Ga+ Ion Irradiation
• Current-driven domain wall motion along ferromagnetic strips with periodically-modulated perpendicular anisotropy
• Magnonic band structure of domain wall magnonic crystals
• Precession-torque-driven domain-wall motion in out-of-plane materials
• Magnetic domain walls in strain-patterned ultrathin films
• Absence of Walker breakdown in the dynamics of chiral Neel domain walls driven by in-plane strain gradients