Open AccessTHEORETICAL INTERPRETATION OF THE ENHANCEMENT OF NEUTRON DIFFRACTION IN AN α-LiIO<sub>3</sub> SINGLE CRYSTAL UNDER THE ACTION OF A DC FIELD
Author(s) -
Zhengyi Xu,
Tiecheng Li,
Ben–Yuan Gu
Publication year - 1979
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.28.96
Subject(s) - diffraction , single crystal , crystal (programming language) , scattering , neutron diffraction , bragg's law , materials science , ion , condensed matter physics , lattice (music) , optics , neutron , physics , molecular physics , nuclear magnetic resonance , nuclear physics , quantum mechanics , computer science , programming language , acoustics
We have noticed in α-LiIO3 single crystals the following experimental facts: (1) Using the conoscopic observation method, it was found the contrast of layer imperfections increasing with the strength of a dc field. (2) Changes take place in the x-ray topography under the action of a dc field. (3) The grown-in spatial variation of lattice parameters were found and measured by an x-ray double-crystal spectrometer. Based on these observations, we infer that space charges (carriers, impurity ions and vacancies) are accumulated at the defects of macroscopic scale, which in turn produces a gradient of lattice parameters under the action of a dc field. We calculated the neutron Bragg scattering cross section for a distorted single crystal using the Born approximation and taking into account the extinction at the same time. Therefrom, the enhancement of diffraction in an α-LiIO3 crystal under the action of a dc field were qualitatively interpreted with good agreement.