Linear magnetoresistance from Dirac-like fermions in graphite

We show that magnetoresistance of Bernal-stacked graphite (with the magnetic field B parallel to the c axis and the current in the ab plane) scales linearly with the magnetic field over an interval of classically weak fields. The linearity is related to the presence of extremely light, Dirac-like carriers near the H(H') points of the Brillouin zone. The Hall resistivity in this interval also shows a nonanalytic B ln vertical bar B vertical bar behavior, and is dominated by holes.