An Investigation on Diamagnetic Levitation of Graphite Sheets

Graphite is a strongly diamagnetic material, and thin sheets of graphite can levitate stably above a 2 x 2 array of cubic permanent magnets with alternate poles facing upward. Two forms of graphite, pyrolytic graphite and isostatic graphite are observed to have different orientation in stable levitation. We hypothesize that this is due to anisotropy of pyrolytic graphite and show that it is using an analytical model. We also go on to investigate the resonant behaviour, equilibrium position and temperature dependence of pyrolytic and isotropic graphite sheets of various sizes levitating in an array of permanent magnets, making use of novel and accessible methods without the need for advanced equipment. Using these results, we characterize the magnetic susceptibility at room temperature experimentally as well as the change in susceptibility with different temperatures. We conclude that increasing temperature leads to reduced magnitude of diamagnetic susceptibility, increasing sheet size leads to decreased frequency of each mode of oscillation for both types of graphite, and the tilting and vertical modes of pyrolytic and isostatic graphite sheets have very similar frequency experimentally.