Hybrid magnonics for short-wavelength spin waves facilitated by a magnetic heterostructure

TL;DR

This paper demonstrates a hybrid magnonic system that enables excitation and strong coupling of short-wavelength magnons (~250 nm) with microwave photons using a magnetic heterostructure, overcoming previous wavelength limitations.

Contribution

It introduces a novel hybrid magnonic system with a magnetic bilayer that facilitates short-wavelength magnon excitation and achieves near superstrong magnon-photon coupling.

Findings

Achieved magnon wavelengths as short as 250 nm.

Demonstrated near superstrong magnon-photon coupling.

Enabled excitation of short-wavelength PSSWs via magnetic heterostructure.

Abstract

Recent research on hybrid magnonics has been restricted by the long magnon wavelengths of the ferromagnetic resonance modes. We present an experiment on the hybridization of 250-nm wavelength magnons with microwave photons in a multimode magnonic system consists of a planar cavity and a magnetic bilayer. The coupling between magnon modes in the two magnetic layers, i.e., the uniform mode in Permalloy (Py) and the perpendicular standing spin waves (PSSWs) in YIG, serves as an effective means for exciting short-wavelength PSSWs, which is further hybridized with the photon mode of the microwave resonator. The demonstrated magnon-photon coupling approaches the superstrong coupling regime, and can even be achieved near zero bias field.