Scanning NV magnetometry is not only suited to measure tiny magnetic fields. It allows to resolve electrical currents (via their magnetic fields) with unprecedented spatial resolution.
We here apply a current to a 100 nm thick Cr/Au u-shaped wire. The current flows through the nanostructure inducing a local magnetic field which is detected using Scanning NV Magnetometry. We show that the local current density (calculated using the magnetic fields) can be used to identify defects in the nanostructure and geometry-specific current behaviour.