Magnetic levitation: Novel material holds promise for unlocking gravity-defying technology
Exploration into levitating materials, substances capable of remaining suspended without any physical contact or mechanical assistance, is underway at the Quantum Machines Unit of the Okinawa Institute of Science and Technology (OIST).
Magnetic fields typically facilitate levitation, with objects like superconductors or diamagnetic materials (those repelled by magnetic fields) able to float above magnets, offering the foundation for advanced sensors with applications in both scientific research and daily life.
Professor Jason Twamley, leading the OIST unit, alongside his team and international partners, has devised a floating platform enveloped within a vacuum, crafted from graphite and magnets. Remarkably, this platform defies conventional power sources, showcasing potential in developing ultra-sensitive sensors for precise measurements. Their findings are detailed in the Applied Physics Letters journal.
Diamagnetic materials, upon exposure to an external magnetic field, generate a magnetic field opposing the external one, thus creating a repulsive force. Consequently, objects composed of diamagnetic materials can hover above potent magnetic fields, a phenomenon utilized, for instance, in maglev trains.
Graphite, a crystalline carbon form commonly found in pencils, exhibits strong repulsion to magnets (highly diamagnetic). Researchers coated a powder of microscopic graphite beads with silica and embedded it in wax, forming a centimeter-sized thin square plate that hovers above magnets arranged in a grid pattern.
While creating a floating platform devoid of external power poses several challenges, the primary hurdle is eddy damping, where an oscillating system loses energy over time due to external forces. This limitation, alongside the need to minimize kinetic energy, must be overcome for the development of frictionless, self-sustaining floating platforms with diverse sensor applications.
To address these challenges, researchers focused on modifying graphite into an electrical insulator, thereby halting energy losses while enabling levitation in a vacuum. By continuously monitoring the platform’s motion and applying feedback magnetic force, the researchers successfully dampened the platform’s movement, effectively cooling it down and enhancing its precision and sensitivity as a sensor.
Professor Twamley’s unit concentrates on leveraging levitating materials to construct mechanical oscillators, systems exhibiting repetitive motion around a central point, with potential applications ranging from pendulums to acoustic systems.
This research endeavors to unlock new possibilities for ultra-sensitive sensors and refine control over oscillating platforms by integrating levitation, insulation, and real-time feedback, pushing the boundaries of materials science and sensor technology.
