Compact, high-performance absolute magnetometer using CrCl₃, a 2D vdW magnet.

Robust magnetometers are essential for many scientific and commercial applications ^[1-2], ranging from physics to biology. Here, we present a fully integrated, robust on-chip magnetometer using a layered 2D vdW magnet. Our magnetometer is a magnetic resonance (MR)-based sensor that uses fundamental physical relationships for precise magnetic field measurements. Unlike other magnetic resonance (MR)-based sensors, such as the NV center, which are usually bulky and expensive, our magnetometer is compact and low-cost. Here, we demonstrated an electron spin resonance-based magnetometer using CrCl₃, a 2D vdW magnet. The advantages of this magnetometer include combining low-cost scotch tape-based thin-film fabrication processes of 2D materials to place a small CrCl₃ sample, measuring ~100 um², on a coplanar waveguide connected to an RF source and RF detector. We demonstrate that the device operates over wide magnetic field ranges, is robust at ambient conditions, and allows for absolute magnetic field sensitivity of < 4 uT Hz^{-1/2 [3]}. This 2D magnet-based magnetometry approach could pave the way for designing high-pixel-density magnetic image sensors for magnetic imaging applications, and potentially on flexible substrates. [1] Adamo, M et al., Sensor Lett. 7, 397–399 (2009), [2] Baker, W., Ambal, K. et al., Nat Commun 3, 898 (2012). [3] A. E. Aregbesola et al., under preparation.