Microcontroller-based magnetometer using a single nitrogen-vacancy defect in a nanodiamond

The measurement of magnetic properties of various physical systems with nanometric spatial resolution raises interest in areas such as materials science, biotechnology, and information storage and processing. In the present work, a microcontroller-based magnetometer was built using a single nitrogen-vacancy defect in a nanodiamond. The implemented nanomagnetometry method is simple and relies on the frequency modulation of the nitrogen-vacancy defect electron spin resonance using square pulses of an externally applied magnetic field and employs a single microwave source. The developed system has a reasonable sensitivity of 4 μT/Hz and is able to measure magnetic field variations at a rate of around 4 mT/s. This system was used for nanoimaging the inhomogeneous spatial magnetic field profile of a magnetized steel microwire, and a spatial magnetic field gradient of 13 μT/63 nm was measured. Besides its usefulness in nanoscale imaging of magnetic fields, the present work can be of interest in the development of compact nanodiamond based magnetometers.