Non-local coupling between antiferromagnets and ferromagnets in cavities

TL;DR

This paper demonstrates that microwaves in a cavity can strongly couple and entangle magnons in both ferromagnets and antiferromagnets, revealing a new link in cavity spintronics.

Contribution

It provides analytical expressions for the coupling strengths and shows that antiferromagnet-ferromagnet coupling is comparable to ferromagnet-ferromagnet coupling.

Findings

Coupling strengths are analytically derived.

Antiferromagnet-ferromagnet coupling is comparable to ferromagnet-ferromagnet.

A robust link between cavity spintronics with ferromagnets and antiferromagnets is established.

Abstract

Microwaves couple to magnetic moments in both ferromagnets and antiferromagnets. Although the magnons in ferromagnets and antiferromagnets radically differ, they can become entangled via strong coupling to the same microwave mode in a cavity. The equilibrium configuration of the magnetic moments crucially governs the coupling between the different magnons because the antiferromagnetic and ferromagnetic magnons have the opposite spins when their dispersion relations cross. We derive analytical expressions for the coupling strengths and find that the coupling between antiferromagnets and ferromagnets is comparable to the coupling between two ferromagnets. Our findings reveal a robust link between cavity spintronics with ferromagnets and antiferromagnets.