Current Sensing Based on Microfabricated Diamond Quantum Magnetometer

In this research, we present an integrated diamond nitrogen-vacancy (NV) center current sensor. The NV sensor device based on the standard microfabrication process is installed in the gap of a yoke and enables a wide range DC electrical sensing and electrical isolation. Two measurement schemes, namely the frequency tracking mode (FTM) and the magnetic balance mode (MBM) are presented. FTM directly detects the magnetic field change in the yoke gap to monitor the primary current, while MBM actively controls the secondary current to compensate the primary current magnetic flux. The frequency tracking scheme allows current sensing in the range of 100 A with a measurement uncertainty of 0.03% and linear error of 0.17%. For the magnetic balance scheme, a measurement uncertainty of 0.075% and a linear error of 0.1% over a range of ±100 A is achieved. This configuration provides a scalable platform for practical applications of quantum current sensing technology.