Dresden 2009 – scientific programme

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MA: Fachverband Magnetismus

MA 14: Poster Ib: Magnetic Materials (1-14); Micro Magnetism/Computational Mag. (15-17); Surface Magnetism (18-22); Spin Structures/Phase Transitions (23-25)

MA 14.20: Poster

Tuesday, March 24, 2009, 10:15–13:00, P1B

Influence of chiral interactions on vortex states in magnetic nanodisks — •A.B. Butenko^1,2, A.A. Leonov^1,2, U.K. Rößler¹, and A.N. Bogdanov¹ — ¹IFW Dresden — ²DIPT Donetsk

Magnetic circular nanostructures exhibit curling vortices which have a sense of rotation and an up/down polarity of the core magnetization. Broken mirror symmetry at surface/interfaces of nanosystems induces chiral Dzyaloshinskii-Moriya interactions, which should strongly affect their magnetic properties [1,2]. In particular, these chiral couplings energetically favour one sense of rotation in a vortex state and suppresses vortices with the opposite chirality [3]. Using a micromagnetic approach, we investigate the influence of these Dzyaloshinskii-Moriya interactions on vortex states in magnetic nanodisks. From numerical solutions for (metastable) equilibrium states with cylindrical symmetry, we calculate shapes and sizes of the vortices as functions of a bias magnetic field and the material and geometrical parameters. These solutions correspond to core structure of vortices in thin film elements with Dzyaloshinskii-Moriya interactions. Calculated magnetic phase diagrams display existence regions for vortices with different chirality and magnetic polarization. As a result, under the influence of the chiral magnetic interactions vortices of opposite chirality should have different sizes. We provide detailed numerical analysis of this effect, which can be applied to measure the strength of the induced Dzyaloshinskii-Moriya coupling. — [1] A. Bogdanov, U.K. Rößler, Phys. Rev. Lett. 87, 037203 (2001). [2] M.Bode et. al., Nature 447, 190 (2007). [3] A. Bogdanov, A. Hubert, J. Magn. Magn. Mater. 195, 185 (1999).