# Single spin sensing of domain wall structure and dynamics in a thin film skyrmion host

## TL;DR

This paper introduces advanced nitrogen vacancy center magnetometry techniques to study the structure and dynamics of skyrmion bubbles in a thin film, revealing insights into their size, helicity, and pinning interactions at room temperature.

## Contribution

It demonstrates a novel scanning method for probing skyrmion bubbles, confirming the Dzyaloshinskii-Moriya interaction's handedness, and analyzes pinning effects on skyrmion size and dynamics.

## Key findings

- Skyrmion bubbles change size in discrete steps based on pinning sites.
- The handedness of the Dzyaloshinskii-Moriya interaction is confirmed.
- Magnetic noise increases near domain walls, indicating interactions.

## Abstract

Skyrmions are nanoscale magnetic structures with features promising for future low-power memory or logic devices. In this work, we demonstrate novel scanning techniques based on nitrogen vacancy center magnetometry that simultaneously probe both the magnetic dynamics and structure of room temperature skyrmion bubbles in a thin film system Ta/CoFeB/MgO. We confirm the handedness of the Dzyaloshinskii-Moriya interaction in this material and extract the helicity angle of the skyrmion bubbles. Our measurements also show that the skyrmion bubbles in this material change size in discrete steps, dependent on the local pinning environment, with their average size determined dynamically as their domain walls hop between pinning sites. In addition, an increase in magnetic field noise is observed near all skyrmion bubble domain walls. These measurements highlight the importance of interactions between internal degrees of freedom of skyrmion bubble domain walls and pinning sites in thin film systems. Our observations have relevance for future devices based on skyrmion bubbles where pinning interactions will determine important aspects of current-driven motion.