Berlin 2018 – scientific programme
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MA: Fachverband Magnetismus
MA 9: Magnetic domain walls
MA 9.4: Talk
Monday, March 12, 2018, 15:45–16:00, EB 202
Dynamical depinning of chiral domain walls — •Simone Moretti1, 2, Michele Voto2, and Eduardo Martinez2 — 1Department of Physics, University of Konstanz, 78457, Konstanz, Germany — 2Department of Applied Physics, University of Salamanca, 37001, Salamanca, Spain
The domain wall depinning field represents the minimum magnetic field needed to move a domain wall, typically pinned by defects or patterned constrictions. From a technological point of view, it represents an important parameter since a small depinning field implies less energy required to move a domain wall and, therefore, an energetically cheaper (domain wall based) device. Conventionally, such field is considered independent on the Gilbert damping since it is assumed to be the field at which the Zeeman energy equals the pinning energy barrier (both damping independent). Consequently, a large or small depinning field is usually interpreted only in terms of the disorder strength of a certain sample. Here we analyse numerically the domain wall depinning field as a function of the Gilbert damping in a system with perpendicular magnetic anisotropy and Dzyaloshinskii-Moriya interaction. Contrary to expectations, we find that the depinning field depends also on the Gilbert damping and that it strongly decreases for small damping parameters. We explain this dependence with a simple one-dimensional model and we show that the reduction of the depinning field is related to the finite size of the pinning barriers and to the domain wall precessional dynamics, connected to the Dzyaloshinskii-Moriya interaction and the shape anisotropy.