Experience of application of small angle X-ray scattering for detection of nano-homogeneities in irizing labrador crystals

Abstract

Irizing and non-irizing labrador have been studied by small-angle X-ray scattering for a wavelength of 1.51angstrom (Cu-alpha). Plates of 0.1-0.2 mm thickness cut perpendicular to the c crystallographic axis were investigated. For the experiment, an X-ray setup with a U-shaped Kratky collimator was used. Two types of scattering were detected for the first time: anisotropic and isotropic. Anisotropic scattering is characteristic only for irizing labradors. It is observed at angles of 1-5 mrad and decreases with increasing scattering angle. The isotropic scattering has a maximum at an angle of 8 mrad, the position of which does not depend on the irization of the sample. Anisotropic scattering is presumably associated with defects in the structure of irizing crystals, characteristic sizes of which are 500-1500 angstroms. Isotropic scattering is apparently determined by structural elements with linear dimensions of 150-180 Å.