Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 42: Focus Session: Curvilinear magnetism

MA 42.5: Vortrag

Donnerstag, 4. April 2019, 11:45–12:00, H38

Curvature induced asymmetric dispersion in nanotubes: the full story — •Attila Kákay — Helmholtz-Zentrum Dresden - Rossendorf, Institute of Ion Beam Physics and Materials Research, 01328 Dresden, Germany

Spin-wave propagation in ferromagnetic nanotubes is fundamentally different than in flat thin films as shown recently[1]. The dispersion relation is asymmetric regarding the sign of the wave vector. As a consequence, spin waves traveling in opposite directions have different wavelength. This purely curvature induced effect originates from the dipole-dipole interaction, namely from the dynamics dipolar volume charges. Such non-reciprocal spin-wave propagation [2] is known for flat thin films with interfacial Dzyalonshiinsky-Moriya interaction. Here, we will discuss in a nanotube with circular cross section the effect of the divergence terms, one by one, on the spin-wave dispersion. The divergence terms in the cylindrical coordinate system together with the term depending on the mean curvature lead to different asymmetries of the dispersion. Moreover, we emphasise the importance of the mean curvature and show that by tailoring it the asymmetry of the dispersion relation can be suppressed with the modulation of the nanotube diameter. As a consequence, we can conclude that the curvature induced magnetochiral effect with magnetostatic origin can be switched on and off by the manipulation of the surface curvature. [1] J.A. Otálora, et. al., Phys. Rev. Lett. 117, 227203 (2016). [2] K. Zakeri, et. al., Phys. Rev. Lett. 104, 137203 (2010).