Scanning nitrogen-vacancy center magnetometry in large in-plane magnetic fields

TL;DR

This paper introduces {110}-cut diamond probes for NV magnetometry, enabling effective scanning of magnetic fields up to 40 mT in large in-plane fields, thus broadening the technique's applicability to in-plane magnetic materials.

Contribution

Fabrication of {110}-cut diamond NV probes that maintain sensitivity in large in-plane magnetic fields, expanding the scope of scanning magnetometry.

Findings

Probes retain sensitivity in fields up to 40 mT.

Demonstrated imaging of Co-NiO domain patterns.

Extended NV magnetometry to large in-plane magnetic fields.

Abstract

Scanning magnetometry with nitrogen-vacancy (NV) centers in diamond has emerged as a powerful microscopy for studying weak stray field patterns with nanometer resolution. Due to the internal crystal anisotropy of the spin defect, however, external bias fields -- critical for the study of magnetic materials -- must be applied along specific spatial directions. In particular, the most common diamond probes made from {100}-cut diamond only support fields at an angle of $\theta = 55^\circ$ from the surface normal. In this paper, we report fabrication of scanning diamond probes from {110}-cut diamond where the spin anisotropy axis lies in the scan plane ($\theta=90^\circ$). We show that these probes retain their sensitivity in large in-plane fields and demonstrate scanning magnetometry of the domain pattern of Co-NiO films in applied fields up to 40 mT. Our work extends scanning NV magnetometry to the important class of materials that require large in-plane fields.