Optical Profiling of Surface-Acoustic-Wave Absorption due to Elastically Driven Ferromagnetic Resonance in Nickel

We optically characterized the local changes in the amplitude and phase of a surface vibration that are associated with the magnetoelastic effect. Pulsed laser interferometry was used to directly probe the amplitude and phase of a surface acoustic wave (SAW) propagating on a nickel thin film in a magnetic field, and a conversion from the angular momentum of the SAW to that of the macroscopic spin system was clearly observed. Pulsed laser interferometry opens the door to local probe and spatial mapping of magnon–phonon conversion in various magnetic materials, which can lead to further progress in fundamental and applied research related to magnetism.