Levitated Sensor for Magnetometry in Ambient Environment

Levitated particle systems provide a promising platform for precision sensing due to their strong isolation from mechanical dissipation and environmental noise. Most room-temperature levitation approaches are primarily sensitive to acceleration, while high-performance magnetic sensing often relies on cryogenic techniques such as superconducting quantum interference devices (SQUIDs) or atomic magnetometers. We report a diamagnetically stabilized, magnetically levitated magnet magnetometer (LeMaMa) operating at room temperature and under Earth's magnetic field. The motion of the levitated ferromagnet is read out optically, enabling sensitive detection of magnetic field fluctuations. Strong spin–lattice coupling in the ferromagnet suppresses spin-projection noise, while magnetic levitation minimizes mechanical losses. We achieve a magnetic field sensitivity of 32 fT/√Hz, comparable to state-of-the-art SQUID and atomic magnetometers. This approach offers a compact, cryogen-free alternative for applications in biology, chemistry, and fundamental physics.