Current conversion in the sliding charge density wave state of NbSe3

High spatial resolution (30–100 μm) X-ray measurements of the satellite positional shift q have been carried out in the upper charge-density-wave state of NbSe3. We determined the spatial distribution of the CDW plastic deformations between electrodes under applied currents. With direct current we observe a steep exponential decrease of q with position x along the sample near the contacts followed by a linear dependence in the central part of the sample. This second regime is attributed to transverse pinning of the CDW dislocations while the first is dominated by phase slip processes. The observed differences between data from direct current and pulsed current measurements indicate a significant, strongly spatially dependent relaxational behaviour of the CDW deformations.