SPIN-ECHO MEASUREMENT OF THE SLIDING SPIN-DENSITY-WAVE VELOCITY IN (TMTSF)2PF6, WHERE TMTSF IS TETRAMETHYLTETRASELENAFULVALENE

We report measurements of the velocity of the sliding spin-density-wav e (SDW) condensate in (TMTSF)2PF6, where TMTSF is tetramethyltetrasele nafulvalene from their modulation of the proton spin echo as a functio n of the SDW current. From these measurements and those of the sliding SDW noise we find that the velocity is consistent with the entire con densate participating in the charge transport and that the wavelength of the pinning potential is half that of the SDW.