The low temperature spin density wave transport: Effects of magnetic filed in (TMTSF)2PF6 and disorder in (TMTSF)2Xʹs

At T = 0.5 K the effects of magnetic field in (TMTSF)2PF6 and disorder in (TMTSF)2X alloys on the nonlinear conduction of spin-density wave states are investigated. The overall electric field dependence of conductivity can be described as a very weak dependence at low fields and a tunneling type expression of σ(E) = σ0exp(−E0/E) for high fields. At low electric fields, the negative magnetoresistance and enhanced conductivity by disorder were observed. At high fields the characteristic field, E0, is increasing as increasing disorder while applying magnetic field only suppresses the conductivity coefficient, σ0, as much as the magnetoresistance for the single particle transport. The consequence of the observations is discussed.