Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 21: Magnetic textures: Transport and dynamics I

MA 21.6: Vortrag

Dienstag, 2. April 2019, 15:15–15:30, H38

Nonreciprocity of spin waves due to the Dzyaloshinskii-Moriya interaction — •Flaviano José dos Santos, Manuel dos Santos Dias, and Samir Lounis — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, D-52428 Jülich, Germany

Can spin-wave measurements help to distinguish the occurrence of skyrmions from antiskyrmions in magnetic materials? The stabilization of one or the other is related to the details and symmetries of the Dzyaloshinskii-Moriya interaction (DMI) [1], which can be determined by measuring its effect on the spin-wave properties [2]. In ferromagnets, the DMI induces a chiral asymmetry on the spin-wave energies of opposite wavevector [3], we then say that the spin-wave spectrum is nonreciprocal [4]. This phenomenon allows us to determine the DMI strength and its sign. However, it is not clear how these DMI-induced asymmetries manifest in complex noncollinear magnetic structures, such as spin spirals and skyrmion lattices. We provide a complete picture on when and how the DMI induces nonreciprocal spin waves in these systems, and how they shall manifest in spin-resolved inelastic electron scattering experiments. Furthermore, we demonstrate an important connection between angular momentum and chiral handedness of a spin-wave mode, which allows us to predict the occurrence of nonreciprocal spin-wave spectrum. -- [1] Hoffmann et al., Nat. Comm. 8, 308 (2017). [2] Di et al., PRL 114, 047201 (2015). [3] Udvardi et al., PRL 102, 207204 (2009). [4] Gitgeatpong et al., PRL 119, 047201 (2017). [5] Dos Santos et al., PRB 97, 024431 (2018).