# Strong Coupling between Microwave Photons and Nanomagnet Magnons

## TL;DR

This paper demonstrates high coupling strength between microwave photons and nanomagnet magnons using lithographically defined superconducting resonators, enabling scalable quantum systems with tunable properties.

## Contribution

It introduces a novel on-chip, scalable design that enhances single spin coupling in nanomagnets, advancing hybrid quantum system development.

## Key findings

- High cooperativity achieved between resonator mode and nanomagnet magnons.
- Scalable, lithographically defined superconducting circuit compatible with quantum applications.
- Coupling strength can be precisely engineered and dynamically controlled.

## Abstract

Coupled microwave photon-magnon hybrid systems offer promising applications by harnessing various magnon physics. At present, in order to realize high coupling strength between the two subsystems, bulky ferromagnets with large spin numbers are utilized, which limits their potential applications for scalable quantum information processing. In this paper, by enhancing single spin coupling strength using lithographically defined superconducting resonators, we report high cooperativities between a resonator mode and a Kittel mode in nanometer thick Permalloy wires. The on-chip, lithographically scalable, and superconducting quantum circuit compatible design provides a direct route towards realizing hybrid quantum systems with nanomagnets, whose coupling strength can be precisely engineered and dynamic properties can be controlled by various mechanisms derived from spintronic studies.