Strong magnon–photon coupling in on-chip CoFe/LiNbO₃ hybrid nanostructures

We demonstrate strong magnon–photon coupling using on-chip arrays of ferromagnetic CoFe nanowires fabricated on a dielectric lithium niobate substrate. A large coupling strength of 1.1 GHz and a cooperativity of 3.1 at a frequency of 24.5 GHz are achieved in CoFe nanowires with a volume of 110 μm³, facilitated by the enhanced spin–photon interaction at the single-spin level. The measured spectra are analyzed using a semiclassical theoretical model that combines the Landau–Lifshitz equation with Maxwell’s equations. Our results provide an on-chip approach to integrated hybrid magnonics based on nanomagnets, offering promising routes for the development of coherent information-processing devices.