ANGULAR MAGNETORESISTANCE OSCILLATIONS AND THE SHAPE OF THE FERMI-SURFACE IN BETA-(ET)2IBR2

Angular magnetoresistance oscillations have been studied systematically for beta-(ET)2 IBr2 in the magnetic field rotating in a series of planes perpendicular to the conducting (a,b)-plane. The oscillations have been found in all studied planes. The shape of the Fermi surface transverse cross-section has been reconstructed using the obtained data. Angular dependence of the slow Shubnikov-de Haas oscillations frequency and some fine features of angular magnetoresistance oscillations permit to discuss also the structure of the Fermi surface longitudinal cross-section. The Fermi surface consists most likely of main cylinders with inclined warping planes and small pockets or necks between them.