On-chip magnon-polaron generation in mode-matched cavity magnomechanics

Magnon polarons are essential for coherent control in acoustic and spintronic devices, but conventional structures based on magnetic thin films on thick piezoelectric substrates suffer from weak magnon-phonon coupling, due to poor spatial mode overlap. The authors overcome this limitation by employing a mode-matched planar magnomechanical system, with a thin piezoelectric film and a micrometer-thick magnetic layer. This configuration enables deeply distributed magnon modes and enhances magnetoelastic interactions with microwave phonons. As a result, the team observes clear formation of magnon polarons, manifested as pronounced avoided crossings in the spectra.