Levitated Sensor for Magnetometry in Ambient Environment

Levitated particle systems have gained significant attention as a rapidly advancing platform for precision sensing, offering low-loss, highly isolated environments by eliminating mechanical contact and associated noise. Current room-temperature levitation techniques are primarily sensitive to acceleration, with magnetic sensing often relying on the Meissner effect, which is impractical under ambient conditions. Here, we demonstrate a diamagnetically stabilized magnetically levitated magnet magnetometer (LeMaMa), where the motion of the magnet is detected optically. Leveraging strong spin-lattice coupling in the ferromagnet to suppress spin-projection noise and minimizing dissipation through levitation, we achieve a sensitivity of 32 fT $/Hz^{1/2}$. This sensitivity is adequate for a wide range of applications in biology, chemistry, and fundamental physics, matching the performance of leading technologies like SQUIDs and atomic magnetometers, while offering the distinct advantage of operating at room temperature and under Earth's magnetic field.