Title: Investigation of phonons and magnons in [Ni80Fe20/Au/Co/Au]N multilayers

Abstract: The interaction between phonons and magnons is a widely developing topic, especially in the field of acoustic spintronics. To discuss this interaction, it is necessary to observe two different waves (acoustic and spin waves) with the same frequency and wavelength. In the Ni80Fe20/Au/Co/Au system deposited on a silicon substrate, we observe the interaction between spin waves and surface acoustic waves using Brillouin light scattering spectroscopy. As a result, we can selectively control (activate or deactivate) the magnetoelastic interaction between the fundamental spin wave mode and surface acoustic waves by adjusting the magnetostrictive layer thickness in the multilayer. We demonstrate that by adjusting the number of layers in a multilayer structure, we can precisely control the dispersion of surface acoustic waves, with minimal impact on the fundamental spin wave mode