High field magnetoresistance of (TMTSF)/sub 2/NO/sub 3/: phase transmons and quantum oscillations

Summary form only given. We report a study of the transverse magnetoresistance of the organic conductor (TMTSF)/sub 2/NO/sub 3/ at ambient pressure, in fields up to 37T and in the temperature range from 2 to 77K. For field along the lowest conductivity axis (c/sup */), two series of quantum oscillations, with temperature independent frequencies of 63T and 247T respectively, are observed in the 2-10K temperature range. The oscillations amplitude of both series decreases when the temperature departs from nearby 4K. Both series are connected to the SDW transition but cannot be accounted for by SdH model. The data is tentatively interpreted, in this temperature range, within the framework of magnetic breakthrough and quantum interferences. The anisotropy of these oscillations is also studied at 4.2K. On the other hand, the magnetic field is found to increase the SDW transition temperature, in agreement with theoretical predictions for SDW phase with imperfect nesting.