  Negatively charged nitrogen-vacancy (NV) centers in diamond have been
extensively studied as a promising high sensitivity solid-state magnetic field
sensor at room temperature. However, their use for current sensing applications
is limited due to the challenge of integration and miniaturization of the
diamond NV sensor. Here, we demonstrate an integrated NV sensor fabricated with
standard microfabrication process. The sensor device incorporated with a
toroidal magnetic yoke enables a high-precision wide range direct current
sensing with galvanic isolation. The performance of the diamond NV current
sensor in an open loop configuration has been investigated. A current measuring
range of 0 A ~ 1000 A with an uncertainty of 46 ppm are achieved. Taking
advantage of dual spin resonance modulation, temperature drift is suppressed to
10 ppm/K. This configuration opens new possibilities as a robust and scalable
platform for current quantum sensing technologies.
