On the interpretation of X-ray diffraction effects in ferroelectric crystals subjected to laser irradiation

In an earlier X-ray investigation of ferroelectric single crystals of LiNbO₃:Fe and triglycine sulfate (3C₂H₅NO₂. H₂SO₄) subjected to laser irradiation [Zhukov, Fetisov & Aslanov (1991). J. Appl. Cryst. 24, 74-76], a large increase (greater than 20%) in the integrated intensities of Bragg reflections was found. An attempt to explain the observed effects is given here with the aid of additional experimental results and consideration of the abnormal photovoltaic effect (APE) followed by a deformation of the domain structure of the crystal.