High field magnetoresistance of (TMTSF)2NO3: phase transitions and quantum oscillations

Transverse magnetoresistance of the organic conductor (TMTSF)2NO3 has been measured at ambient pressure, in fields up to 37T and in the temperature range 2–77K. For field along the lowest conductivity axis (c∗), the magnetic field is found to increase the SDW transition temperature, in agreement with theoretical predictions for SDW phase with imperfect nesting. On the other hand, two series of quantum oscillations, with frequency of 63T and 246T respectively, are observed in the 2–10K range. Both series are connected to the SDW transition but cannot be accounted for by Shubnikov-de Haas model. Anisotropy of these oscillations is studied at 4.2K.