Optimization of acoustically-driven ferromagnetic resonance devices

Abstract

Acoustically-driven ferromagnetic resonance (ADFMR) has recently emerged as a powerful scientific test-bed toward understanding complex interactions between phonons and magnons. In this technique, a traditional surface acoustic wave (SAW) delay-line filter interfaces with a ferromagnetic thin-film which can be driven into precession at the ferromagnetic resonance (FMR) frequency by the SAWs. SAW filters are used extensively in industry, but in the context of ADFMR, their design considerations are largely absent from the literature. We produced a variety of ADFMR devices by systematically changing parameters including the material and the number of pairs of interdigital transducers, the ferromagnetic thin-film growth technique, and the presence or the absence of a capping layer on the ferromagnetic thin-film. We quantitatively compare results by adapting traditional ferromagnetic resonance techniques. This work describes the parameters relevant to the development and optimization of SAW-driven FMR.