ANGULAR DEPENDENT MAGNETORESISTANCE OSCILLATION IN&

The angular dependent magnetoresistance oscillation (ADMRO) of the stage-2 IBr graphite intercalation compound (GIC) was studied between 1.8 K and 110 K in magnetic fields between 1 and 9 T. There was a series of peaks in the c-axis resistance as the field direction was changed from the c axis to the (001) plane. The field independence of the angular positions of the peaks, showing that the oscillation is not from the Shubnikov-de Haas effect, and the presence of the oscillation at high temperatures indicate that the effect is semiclassic. The location and the relative amplitudes of the peaks show that the ADMRO in this compound does not follow the predictions for the symmetrical corrugation model of the cylindrical Fermi surface. The reason is attributed to the presence of two cylindrical Fermi surfaces and zone folding of the Fermi surface by the periodicity of the IBr lattice in this compound.