High pressure and high field studies of alpha-[(CH3)(2)(C2H5)(2)N][Ni(dmit)(2)](2)

The magnetoresistance of alpha-[(CH3)(2)(C2H5)(2)N][Ni(dmit)(2)](2) has bee n studied at ambient pressure in magnetic fields of up to 60 T and under hy drostatic pressures of up to 6 kbar in fields of up to 17 T. The high field measurements indicate a very simple Fermi surface. Measurements in medium fields, however, indicate several quantum oscillation frequencies, whose we ight gets reduced with increasing field in favour of the major gamma-orbit. The low field alpha- and beta-orbits exhibit a strong pressure sensitivity . Whereas no quantum oscillations were observed at 2 kbar, shifted alpha-an d beta-frequencies occur at a pressure of 6 kbar.