On-chip levitation of ferromagnetic microparticles

TL;DR

This paper presents a scalable, room-temperature on-chip magnetic levitation platform for ferromagnetic microspheres, enabling high-frequency librational modes and potential quantum applications.

Contribution

It introduces a novel on-chip magnetic levitation system that overcomes limitations of previous methods, supporting stable levitation at room temperature with high eigenfrequencies.

Findings

Successfully levitated a 6.5 μm ferromagnetic microsphere.

Achieved librational eigenfrequencies exceeding 10 kHz.

Platform is scalable, tunable, and compatible with quantum and sensing applications.

Abstract

Levitation of microscopic objects in vacuum combines exceptional environmental isolation with precise control of their dynamics, pushing the limits of sensing and macroscopic quantum physics. In particular, magnetic levitation allows a large range of particle sizes, while avoiding detrimental effects from high-intensity optical trapping beams and electric field noise. However, existing diamagnetic and Meissner levitation approaches are typically constrained by low mechanical eigenfrequencies, limited integrability with other systems due to bulky coils or magnets, and, for Meissner levitation, the need for cryogenic operation. Here, we demonstrate a room-temperature on-chip magnetic levitation platform capable of stably levitating a nanogram (6.5 micrometer radius) ferromagnetic microsphere. The platform is scalable and tunable, and supports librational modes with eigenfrequencies exceeding 10 kHz. Further miniaturization and coupling to solid-state spin qubits could enable cooling to the quantum ground state. Beyond quantum experiments, this architecture enables integrated precision sensing and studies of isolated ferromagnet thermodynamics.