Exploiting magnetic hysteresis to couple an acoustic wave to magnetic dynamics
Magneto-acoustic coupling has proved an interesting approach to generate spin waves, the magnetic excitations that could encode information in new components. Until now, the role of magnetic hysteresis – i.e. the fact that the orientation of magnetization depends not only on the current magnetic field, but also history – was poorly understood. A team of researchers at INSP have elucidated this with a simple model and a material with a well-controlled hysteresis, FeRh. This should help improve future magneto-acoustic components.
Reference
Vythelingum, AK; Tremblais, T; Nguyen, DB; Ourdani, D; Dandeu, E; Laude, V; Gourdon, C; Thevenard, L
Role of Coercivity in Surface Acoustic Wave Driven Ferromagnetic Resonance
ACS APPLIED ELECTRONIC MATERIALS, May 1 2025
Caption
The acoustic amplitude is measured after travelling across a magnetic layer. It depends on the sweeping direction of the applied field. Its minima correspond exactly to the static coercivity of the magnetization. A simple model considering the layer as a single spin has made it possible to account for this.
