Dresden 2014 – scientific programme
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MA: Fachverband Magnetismus
MA 29: Magnetization Dynamics II
MA 29.10: Talk
Wednesday, April 2, 2014, 17:30–17:45, HSZ 401
Supermagnonic Bloch point propagation in cylindrical nanowires — •Christian Andreas1,2, Attila Kákay1, and Riccardo Hertel2 — 1Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany — 2Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504, Strasbourg, France
Bloch points (BPs) [1,2] are micromagnetic singularities that can play a decisive role in magnetic switching processes. The archetypal example is a soft-magnetic cylinder [3], where a BP resides in the center of a vortex domain wall (VDW). Micromagnetic theory is not capable to treat BPs and their dynamics correctly, as they represent topological defects and singularities. We used our multiscale-multimodel code [4] that combines an atomistic Heisenberg model with a finite element micromagnetic algorithm to trace Bloch points and to study the dynamics of VDWs driven by an external magnetic field. The results show that, owing to the high stability of VDWs, the combination of BP and VDW can smoothly propagate at supermagnonic velocities above 1000 m/s when it is driven by fields of only a few mT. We further find a limiting BP/VDW propagation velocity that remains unchanged for a broad range of magnetic field values; a feature that could be advantageous for domain-wall based magnetic storage or logic devices.
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