Figure 5. Relation of voltage to phase and vortex velocity.

(a) The temporal evolution of the phase difference (blue line) and the temporal derivative of the phase difference (red dash-dots) measured between the voltage contacts, for the situation corresponding to Fig. 3. (b) The crossing time of one vortex as a function of the pinning period τ, for different applied current. Horizontal dashed lines represent the vortex crossing time in the pinning-free sample. Open dots indicate τ = τ^*, the period of the pinning for which the vortex crossing time becomes the same as in the absence of pinning (consequently, the corresponding voltages match, c.f. Fig. 2).