The elastic coupling between a magnetic film and the substrate is desired in SAW-FMR devices and in magnetoacoustics [1–3] when one harnesses the interaction between a surface acoustic wave (SAW) hosted by a piezoelectric substrate and the magnetization dynamics of a magnetic film on top. We first designed an experiment specifically meant to quantify the magneto-elastic and magneto-rotation field that arise from the mechanical deformations induced by a SAW. For this we prepared magnetic discs possessing a vortex ground state. The discs can be excited either by a remotely generated SAW or by an inductive antenna placed on top of the disc. The vortex dynamics can be measured by magnetic resonance force microscope (MRFM). The antenna has broadband frequency capability and can induce the gyrotropic dynamics of the vortex. The SAWs can also induce this dynamic, provided that the vortex gyration frequency is resonant with that of the SAW [4]. This ability to excite the same dynamics with a classical antenna or with magneto-acoustic interaction allows to quantify the effective magneto-elastic and magneto-rotation fields. It appears that the symmetry of the magneto-acoustic interactions deserved to be revisited. We did such analysis using micromagnetic simulation and analytical calculations. In addition, the symmetry of the coupling can be conveniently studied when studying the coupling of spin waves (SWs) in synthetic antiferromagnets (SAFs) to SAWs [5]. For this we calculated the layer-resolved susceptibility tensor of a SAF, the effective magneto-elastic and magneto-rotation fields associated to a travelling elastic wave, and the power irreversibly transferred by the elastic wave to the magnetic layers. In particular, we showed that in SAF the complementary angular dependencies of the acoustic and optical SW modes makes it possible to excite spin waves for any relative orientation of magnetization and acoustic wavevector.

[1] M. Weiler et al. Phys. Rev. Lett. 106, 117601 (2011).
[2] P. Kuszewski et al.  Phys. Rev. Appl. 10, 034036 (2018).
[3] P. Rovillain et al.  Phys. Rev. Appl. 18, 064043 (2022).
[4] R. L. Seeger et al. under review, arXiv:2409.05998.
[5] R. L. Seeger et al.  Phys. Rev. B. 109, 104416 (2024)

- List of authors and affiliations : 
R. L. Seeger(a,b), F. Millo(a), L. La Spina(c), V. Laude(c), A. Bartasyte(c), S. Margueron(c), G. Soares(b) , L. Thevenard(a), C. Gourdon(a), J.-V. Kim(a), C. Chappert(a), A. Solignac(b), G. de Loubens(b), T. Devolder(a)
(a) Centre de Nanosciences et de Nanotechnologies, CNRS, Univ. Paris-Saclay 91120 Palaiseau, France
(b) SPEC, CEA, CNRS, Univ. Paris-Saclay, 91191 Gif-sur-Yvette, France
(c) Univ, de Franche-Comté, CNRS, Institut FEMTO-ST, 26 rue de l’Epitaphe, 25000 Besançon, France
(d) Institut des Nanosciences de Paris, Sorbonne Université,CNRS, UMR 7588, 4 place Jussieu, F-75005 Paris, France

- Bio : Rafael Lopes Seeger holds a Bachelor's and a Master's degree in Physics (2018) from the Federal University of Santa Maria (UFSM), Brazil, and a Ph.D. in Physics (2021) from the Université Grenoble-Alpes at the SPINTEC laboratory in Grenoble, France. Since 2022 he is a postdoctoral researcher working at SPEC (CEA-Saclay ) and C2N (CNRS, Université Paris Saclay) on projects involving magnon-phonon coupling and nonlinear effects in spin waves.