Magnomechanics in a suspended beam*

Cavity optomechanical systems have long been the preferred system for studies investigating the interactions between photons and mechanics. However, their structural configuration limits the possibility to integrate multiple systems into a single chip. Our work is focused towards establishing magnomechanical analogies to optomechanics, where the electromagnetic cavity is replaced by the ferromagnetic resonance in a magnetic film. Our theoretical calculations demonstrate the existence of a coupling between the mechanical and the magnetic modes in the beam in the presence of an initial static deformation, which is due to a mismatch of the elastic coefficients and deposition induced strains. The experimental structure is a suspended bilayer beam of CoFeB (50 nm) and Al (100 nm) such that the mechanical as well as the magnetic modes can be excited individually. We measure the mechanical sideband around the Kittel frequency for different magnetic fields as well as for constant beam displacements and demonstrate the magnon – mechanical coupling.