X-ray diffraction from pinned charge density waves

We present an x-ray study of doped charge density waves systems. When a 2 k appa(f)-charge density wave is strongly pinned to impurities; an interferen ce effect gives rise to all asymmetry between the intensities of the +2 kap pa(f) and -2 kappa(f) satellite reflections. Moreover, profile asymmetry of the satellite reflections indicates the existence of Friedel oscillations (FOs) around the defects. We have studied these effects in V- and W-doped b lue bronzes. A syncrotron radiation study of the V-dopted blue bronze clear ly reveals the presence of FO around the V atoms.