Properties of the commensurate spin-density-waves

In an earlier study we reported that (TMTSF)2PF6 samples from a particular batch showed characteristics of commensurate spin-density-waves. We re-investigated the same sample and confirmed the same characteristics. Moreover, the magnetic field applied perpendicular to the most conducting plane gave a completely different result. The threshold electric field decreased rapidly by a factor 4 upon applying a magnetic field of 3 T and then increased slightly upon increasing the field further. The latter behavior is reminiscent of normal incommensurate spin-density-waves. We also investigated the temperature dependence of the threshold field under a fixed magnetic field. As the magnetic field increased, the zero field behavior disappeared fast and an increase of threshold field was observed which might indicate the recovery of the weak pinning limit of the incommensurate spin-density-wave.