Ferromagnetic- and Superconducting-Like Behavior of Graphite.

We have identified ferromagnetic- and superconducting-like magnetization hysteresis loops in highly oriented pyrolytic graphite samples below and above room temperature. We also found that both behaviors are very sensitive to low-temperature—as compared to the sample synthesis temperature—heat treatment. The possible contribution of magnetic impurities and why these do not appear to be the reason for the observed phenomena is discussed. [ABSTRACT FROM AUTHOR]