Widefield in situ NV-MOKE microscopy for magnetometry

We present here a magnetic imaging setup for magnetic thin films, allowing two methods of probing: Magneto-Optical Kerr Effect and Nitrogen-vacancy probing. The first mode allows a quick viewing of the magnetic domains, with a resolution limited by optical diffraction, but does not provide quantitative measurement of the magnetization. This information is obtained by adding the complementary NV imaging mode, which consists of the widefield imaging of an NV-doped diamond plate on top of the magnetic film. We can then image the magnetic domains with high resolution and simultaneously measure the total magnetic moment of the order of 10⁻¹⁵ A m² from the influence of the stray magnetic field on the NV optically detected magnetic resonance spectrum.