Density wave defects in chromium probed by coherent X-rays

We report on the study of density wave defects in pure chromium. The incommensurate satellite reflections associated with the spin density wave (SDW) and with the charge density wave (CDW) have been explored in condition of non-resonant coherent X-ray diffraction. First, a line shapes analysis of the SDW and CDW reveals that the correlation length of the CDW is smaller than the SDW one. This observation shows that the CDW in chromium is not stabilized by a pure magnetostrictive coupling with the SDW. Then, coherent X-ray diffraction profiles obtained on the SDW reflection are consistent with the presence of an edge dislocation of the magnetic order, embedded at a few micrometers from the surface of the sample. Beyond the specific case of dislocations in chromium, this work may open up the way in studying magnetic defects embedded in the bulk. (C) 2008 Elsevier B.V. All rights reserved.