Investigation of structural perfection in CsDSO4, CsHSO4 and CsH2PO4 single crystals by high-resolution X-ray diffraction techniques

Pure shears of CsDSO4, CsHSO4 and CsH2PO4 belonging to monoclinic crystal system, have been studied for the first time using the methods of diffraction reflection curves and three-crystal X-ray diffractometry. It is shown that the crystals are perfect enough and scattering upon them obeys laws of dynamic theory. Dislocations with the density of approximately 104-105 cm-2 are the main defects of the structure. For crystals of CsDSO4 and CsHSO4 considerable negative deformations δd/d≅-10-3 in near the surface layers at room temperature were detected. It is shown that the density of dislocations in near the surface layers of CsDSO4 and CsHSO4 monocrystals increases in time