Diamagnetic levitation and thermal gradient driven motion of graphite

Abstract

We theoretically study the diamagnetic levitation and the thermal-driven motion of graphite. Using the quantum-mechanically derived magnetic susceptibility, we compute the equilibrium position of levitating graphite over a periodic arrangement of magnets, and investigate the dependence of the levitation height on the susceptibility and the geometry. We find that the levitation height is maximized at a certain period of the magnets, and the maximum height is then linearly proportional to the susceptibility of the levitating object. We compare the ordinary AB-stacked graphite and a randomly stacked graphite, and show that the latter exhibits a large levitation length particularly in low temperatures, because of its diamagnetism inversely proportional to the temperature. Finally, we demonstrate that the temperature gradient moves the levitating object towards the high temperature side, and estimate the generated force as a function of susceptibility.

Dynamic and fluctuation properties of a graphene disk levitated by a diamagnetic force in air

“…The temperature dependence of the magnetic permeability [22,36] enables the magnetic force acting on a graphene disk to change. Illumination is a useful method for heating the levitated graphene disk [37][38][39][40], and optical control has been demonstrated for graphite disks [41,42]. If the temperature of a nanographene disk is increased from 300 K to 450 K, the magnetic permeability changes from −2.6 × 10 −7 m 3 kg −1 to −1.9 × 10 −7 m 3 kg −1 , respectively.…”

Sonomaglev: Combining acoustic and diamagnetic levitation

“…Ref. 41). In contrast to the oscillating surface forces applied in acoustic levitation, diamagnetic levitation applies a constant body force that counteracts the force of gravity throughout the levitated object at the molecular level, and so closely mimics the weightless conditions on board an orbital or parabolic flight, or in a drop tower.…”