Highly stable diamagnetically levitated mechanical resonators with large masses exceeding 1.5 gram

We present resonant mechanical systems that exploit diamagnetic levitation to eliminate clamping loss and achieve high quality factors at room temperature, toward enabling precision sensing applications. By engineering centimeter-scale composite plates formed by dispersing graphite microparticles in insulating epoxy and levitating them above arrayed permanent magnets, we demonstrate stable, full levitation of composite devices with masses exceeding 1.5 grams. Simulations and experimental measurements confirm stable three-dimensional trapping. Suppression of eddy current damping allows the levitated resonators to reach quality factors exceeding 32,000 in moderately high vacuum (∼25 µTorr) at room temperature. Residual velocity measurements and closed-loop frequency tracking using a phase-locked loop reveal near-zero passive motion and exceptional frequency stability, with Allan deviation down to 1.5 × 10^-6 at 20 s averaging time, demonstrating excellent stability of the levitation system. Furthermore, the devices can readily operate as sensitive magnetometers. These findings position levitated graphite composite plates as a scalable, low-dissipation candidate platform for next-generation inertial sensors and high-performance resonant systems.