engleski

Sliding spin-density waves: Studies of conduction noise, magnetic field dependence and Hall resistivity

We have studied the current-voltage characteristics of the (TMTSF)_2PF_6 in the spin density wave state (SDW), and in zero and finite external magnetic field. For the oscillating part of the nonlinear voltage response to the applied DC eletric field, the fundamental frequency distribution (as a function of this field) and a nonlinear relation between the frequency and the SDW current reveal the growth of parallel conduction channels characterized by lower velocities and larger cross-sections. The number of fundamental frequencies, their amplitude and the level of low-frequency noise as well as the depinning behaviour provide a consistent indication of the sample inhomogeneities and associated local field variations, and might be well understood within the framework of the phase slippage model. The increase of the threshold electric field with the applied magnetic field can be explained by the Bjeliš-Maki theory, if the imperfect nesting is taken into account. Finally, the electric field dependence of the Hall resistivity is consistent with the sliding mechanism of the SDW conduction.

organic superconductors; collective modes; one-dimensional conductors; spin-density waves; noise processes; galvanomagnetic and other magnetotransport effects

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