We conduct a feasibility study of nitrogen-vacancy (NV) ensemble magnetometry of the two-dimensional ferromagnet Cr2Ge2Te6 (CGT). The studied sample consists of thin flakes of exfoliated CGT...Show moreWe conduct a feasibility study of nitrogen-vacancy (NV) ensemble magnetometry of the two-dimensional ferromagnet Cr2Ge2Te6 (CGT). The studied sample consists of thin flakes of exfoliated CGT stamped onto a diamond with shallow NV centers. First, we simulate the NV center response to the magnetic stray fields produced by a monolayer of CGT and conclude a good signal to noise ratio should be attainable in a shot noise limited picture. Subsequent room temperature photo luminescence experiments reveal two key challenges: optical dimming underneath the samples and inherent low contrast of the NV electron spin resonance (ESR) spectrum. We can explain the optical dimming by a near-surface nanophotonic effect. The low observed contrast can partially be accounted for by the ionization of the shallow NV centers to the neutral charge (NV0). Also, it is found that contrast can be largely regained by rigorous cleaning of the diamond surface.Show less
The low noise amplifier from Bastiaans et al. [1] is improved by increasing the bandwidth, such that measurement time is reduced. Instead of a single common-source transistor, a cascode setup is...Show moreThe low noise amplifier from Bastiaans et al. [1] is improved by increasing the bandwidth, such that measurement time is reduced. Instead of a single common-source transistor, a cascode setup is used. A common-source is followed by a common-gate which is followed by a common-drain. The gain (V/V) of the amplifier is estimated to be 22. The cascoding reduces the miller capacitance from 22pF to approximately 2pF. The input noise current is estimated to be 19fA/√Hz and the voltage noise 0.2nV/√Hz. The power dissipation is estimated at 2mW.Show less
