Tunable magnetic field source for magnetic field imaging microscopy

TL;DR

This paper introduces a compact, power-efficient, tunable magnetic field source for magnetic field imaging microscopy, demonstrating precise control and homogeneity of magnetic fields at the micrometer scale.

Contribution

The work presents a novel magnetic field source design with tunable amplitude and high homogeneity, validated through simulations and experiments.

Findings

Tunable magnetic field from 1 mT to 222 mT achieved.

Magnetic field homogeneity of 2 ppm/μm demonstrated.

Good agreement between simulation and experimental results.

Abstract

In this work we present a novel, compact, power efficient magnetic field source design for magnetic field imaging microscopy. The device is based on a pair of diametrically magnetized permanent magnet cylinders with electro-mechanical rotation control and ferrite field concentrators. A Hall probe and NV centers in diamond are used to demonstrate a proof of concept of a proposed magnetic field setup and to characterise the homogeneity of the produced magnetic field on a micrometer scale. Numerical simulation results are compared with experimental results showing good agreement of the distribution of the magnetic field in the setup. As a result, a magnetic field source with a tunable field amplitude in the range from 1 mT to 222 mT is demonstrated, achieving a magnetic field homogeneity of 2 ppm/$\mu$m or 0.5 $\mu$T/$\mu$m at 222 mT in a 25$\times$25 $\mu$m field of view.