Dynamics of coupled vortices in a pair of ferromagnetic disks

TL;DR

This paper experimentally demonstrates how coupled vortex gyration modes in ferromagnetic disks can be resonantly excited and exhibit splitting into bonding and anti-bonding states, resembling diatomic molecules.

Contribution

It provides the first experimental observation of resonant excitation and mode splitting of coupled vortex gyrations in ferromagnetic disks with variable separation.

Findings

Coupled gyration modes can be resonantly excited by ac current.

The gyrotropic mode splits into higher and lower frequency modes.

The vortex pair behaves like a diatomic molecule with bonding and anti-bonding states.

Abstract

We here experimentally demonstrate that coupled gyration modes can be resonantly excited primarily by the ac current in a pair of ferromagnetic disks with varied separating distance. The sole gyrotropic mode clearly splits into a higher and a lower frequency modes for different configurations of polarities via dipolar interaction. These experimental results indicate that the magnetostatically coupled pair of vortices behaves similar to a diatomic molecule with bonding and anti-bonding states. These findings lead to the possible extension of designing the magnonic band structure in a chain or an array of vortices.