Fermi Surface of Magnesium. IV. Magnetoresistance Study of Open Trajectories

Abstract

Measurements of the magnetoresistance of high-purity single crystals of magnesium were made in order to determine the magnetic field directions for which open trajectories exist on the magnesium Fermi surface. Nine distinct series of open trajectories with net directions parallel to the basal plane of reciprocal space were observed. These trajectories have basic periodicities extending up to nine Brillouin zones and result from magnetic breakdown between the monster and cigar. The magnetic field directions for which these trajectories exist are shown to be in excellent agreement with the predictions of the Fermi-surface model proposed by Kimball, Stark, and Mueller. Measurements for the open trajectory parallel to the hexagonal axis in reciprocal space are also reported; these show a clear indication of the onset of magnetic breakdown across the spin-orbit gap separating the monster and the cap.