Koerber, Lukas and Zimmermann, Michael and Wintz, Sebastian and Finizio, Simone and Kronseder, Matthias and Bougeard, Dominique and Dirnberger, Florian and Weigand, Markus and Raabe, Jorg and Otalora, Jorge A. and Schultheiss, Helmut and Josten, Elisabeth and Lindner, Jurgen and Kezsmarki, Istvan and Back, Christian H. and Kakay, Attila (2021) Symmetry and curvature effects on spin waves in vortex-state hexagonal nanotubes. PHYSICAL REVIEW B, 104 (18): 184429. ISSN 2469-9950, 2469-9969
Full text not available from this repository. (Request a copy)Abstract
Analytic and numerical studies on curved magnetic nano-objects predict numerous exciting effects that can be referred to as magneto-chiral effects, which do not originate from intrinsic Dzyaloshinskii-Moriya interaction or interface-induced anisotropies. In contrast, these chiral effects stem from isotropic exchange or dipole-dipole interaction, present in all magnetic materials, which acquire asymmetric contributions in case of curved geometry of the specimen. As a result, for example, the spin-wave dispersion in round magnetic nanotubes becomes asymmetric; namely, spin waves of the same frequency propagating in opposite directions along the nanotube exhibit different wavelenghts. Here, using time-resolved scanning transmission x-ray microscopy experiments, standard micromagnetic simulations, and a dynamic-matrix approach, we show that the spin-wave spectrum undergoes additional drastic changes when transitioning from a continuous to a discrete rotational symmetry, i.e., from round to hexagonal nanotubes, which are much easier to fabricate. The polygonal shape introduces localization of the modes to both the sharp, highly curved corners and flat edges. Moreover, due to the discrete rotational symmetry, the degenerate nature of the modes with azimuthal wave vectors known from round tubes is partly lifted, resulting in singlet and duplet modes. For comparison with our experiments, we calculate the microwave absorption from the numerically obtained mode profiles, which shows that a dedicated antenna design is paramount for magnonic applications in 3D nanostructures. To our knowledge these are the first experiments directly showing real space spin-wave propagation in 3D nano-objects.
| Item Type: | Article |
|---|---|
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Chair Professor Huber > Group Dominique Bougeard |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 13 Sep 2022 08:21 |
| Last Modified: | 13 Sep 2022 08:21 |
| URI: | https://pred.uni-regensburg.de/id/eprint/47931 |
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