Graphite has been known as a typical diamagnetic material and can be levitated in the strong magnetic field. Researchers have shown that the magnetically levitating pyrolytic graphite can be moved in the arbitrary place by simple photoirradiation. It is notable that the optical motion control system described in this paper requires only NdFeB permanent magnets and light source. The optical movement is driven by photothermally induced changes in the magnetic susceptibility of the graphite. Moreover, we demonstrate that light energy can be converted into rotational kinetic energy by means of the photothermal property. We find that the levitating graphite disk rotates at over 200 rpm under the sunlight, making it possible to develop a new class of light energy conversion system.
The researchers predict that the ability to control maglev-based motion with a laser could lead to the development of maglev-based actuators and photothermal solar energy conversion systems. Applications could include a low-cost, environmentally friendly power generation system and a new type of light-driven transportation system.
“At this moment, we are planning to develop a maglev turbine blade suitable for this system,” Abe said. “In this case, it is predicted that friction disrupts the rotation of the maglev turbine. Therefore, we would like to develop a light energy conversion system with a high energy conversion efficiency with reference to the so-called MEMS (Microelectromechanical Systems) technique.
“As for the actuator, the maglev graphite can convey anything that has almost the same weight as the levitating graphite disk. So, if the scale expansion of the photo-actuator system is achieved, it is not a dream that a human on the maglev graphite can drive himself.”
The technique is very simple and fundamental, it is expected to apply to various daily living techniques, such as transportation systems and amusement, as well as photo-actuators and light energy conversion systems