The Interaction between Surface Acoustic Waves and Spin Waves: The Role of Anisotropy and Spatial Profiles of the Modes.

Grzegorz Centała,Hubert Głowiński,Nandan K P Babu,Szymon Mieszczak,Miłosz Zdunek,Jarosław W Kłos,Sławomir Mielcarek,Piotr Graczyk,Aleksandra Trzaskowska

doi:10.1021/acs.nanolett.0c03692

Abstract

The interaction between different types of wave excitation in hybrid systems is usually anisotropic. Magnetoelastic coupling between surface acoustic waves and spin waves strongly depends on the direction of the external magnetic field. However, in the present study we observe that even if the orientation of the field is supportive for the coupling, the magnetoelastic interaction can be significantly reduced for surface acoustic waves with a particular profile in the direction normal to the surface at distances much smaller than the wavelength. We use Brillouin light scattering for the investigation of thermally excited phonons and magnons in a magnetostrictive CoFeB/Au multilayer deposited on a Si substrate. The experimental data are interpreted on the basis of a linearized model of interaction between surface acoustic waves and spin waves.

Highlights

The interaction between different types of wave excitation in hybrid systems is usually anisotropic
S tudies of the coupling of elastic waves with other wave excitations, including spin waves, in nanostructures are experiencing a revival, which is mostly due to the progress in experimental techniques.[1−12] Magnetostrictive systems are promising for switching the magnetic configuration and controlling spin-wave propagation by nonmagnetic means.[5,13−15] The strategy to use strain or an electric field is technically less problematic than controlling the magnetic system by magnetic field for the realization of logic gates,[5] magnetic recording,[13] or signal processing.[16,17]
We consider the generic structure, a magnetostrictive layer deposited on a nonmagnetic substrate, with the magnetization dynamics in the layer coupled to the elastic excitations concentrated on the surface of the structure

Summary

Author Contributions

H.G. fabricated the sample. N.K.P.B, M.Z., A.T., and S. Miel. carried out the BLS measurements. P.G., G.C., S. Mies., and J.W.K. developed the theoretical model and performed numerical simulations. All the authors discussed the results and commented on the manuscript. Notes The authors declare no competing financial interest.

■ ACKNOWLEDGMENTS

■ REFERENCES