Magnetic and electrical field detection using NV-based AFM

We develop a homemade NV-based scanning microscopy to detect both magnetic and electrical field induced by tips we used. As for the magnetic field, the Ni tip is required to provide magnetic field and field gradient on the surface of diamond membrane. The ODMR shift is observed during the Ni tip moving around a NV center, and we observe isomagnetic circle by ODMR mapping which shrinks to about 20nm indicating the actual location of the NV center.
Besides, the sensor we made allow us to apply bias voltage between metal tip and diamond. And the electrical field can be also measured by ODMR and Pulsed ODMR shift. Our results show the electrical field up to 100V/um which maybe controls the charge state of the NV center.