Eigenmodes of Neel skyrmions in ultrathin magnetic films

TL;DR

This study investigates the eigenmodes of Ne9el skyrmions in ultrathin magnetic films, revealing phase-dependent modes and their behaviors, which are crucial for understanding skyrmion dynamics and potential microwave applications.

Contribution

It provides a detailed micromagnetic analysis of skyrmion eigenmodes across different phases, highlighting the effects of interfacial DMI and magnetic fields on these modes.

Findings

Breathing, CCW, and CW modes exist in the SkL phase.

Only breathing and CCW modes are present in the ISk phase.

CCW mode frequency is unaffected by phase transition.

Abstract

The static and dynamic states of N\'eel skyrmions in ultrathin ferromagnetic films with interfacial Dzyaloshinskii-Moriya interaction (DMI) have been micromagnetically simulated as functions of the interfacial DMI strength and applied static magnetic field. Findings reveal that while the breathing, counterclockwise (CCW) and clockwise (CW) rotational eigenmodes exist in the skyrmion lattice (SkL) phase, only the first two modes are present in the isolated skyrmion (ISk) phase. Additionally, the eigenfrequency of the CCW mode is insensitive to the magnetic-field driven SkL-ISk phase transition, and the inter-skyrmion interaction is largely responsible for exciting the CW mode in the SkL phase. The findings provide physical insight into the dynamics of the phase transition and would be of use to potential skyrmion-based microwave applications.