Topological spin textures as spin-wave emitters

The investigation of propagating spin waves is a key topic of magnetism research [1]. For the excitation of short wavelengths, it was typically necessary to either use patterned transducers with sizes on the order of the desired wavelengths (striplines or point-contacts) or to generate such spin waves parametrically by a spatially uniform double-frequency microwave signal [2]. Recently, we found a novel mechanism for the lo- cal excitation of spin waves, which overcomes the lower wavelength limit given by the minimum patterning size. This method utilizes the translation of natural topological spin textures, e.g. the gyration of spin vortex cores, to generate spin waves [3]. Yet in terms of signal transfer, spin waves excited by a 0D defect, propagating isotropically in a 2D matrix su er from a geometry induced amplitude decay. This decay is prevented when the dimensionality di erence between source and host matrix is reduced to one. Here we will show that this can be achieved in vortex pair systems with moderate uniaxial intrinsic anisotropy, where domain walls may act both as 1D channels for direc- tional wave propagation and as emitters for 2D plane waves [4]. Finally, we will address vortex core induced spin-wave excitation in single layer lms [5]. [1] A.V. Chumak et al., Nat. Phys. 11, 453 (2015). [2] A.G. Gurevich, G.A. Melkov, Magnetization Oscillations and Waves. New York CRC, 1996. [3] S. Wintz et al., Nat. Nanotechnol. 11, 948 (2016).