THE ANOMALOUS BACK DIFFRACTION PSEUDO-KOSSEL PATTERNS OF LiNbo3 CRYSTAL IN THE VICINITY OF 75℃

Abstract

It is found that the diffraction, obtained by using X-ray divergent beam technique-back reflection Kossel method, of pure and Ti-diffused LiNbO3 crystals become abnormal in the vicinity of 75℃.The Pseudo-Kossel lines of such crystal planes as (11010), (01110), (0118), (1108), (03312), (33012), are found to be severely distorted but still continuous. The pattern's distortion shows approximately two-fold symmetry about x-plane and therefore the crystal's triad axis of symmetry along x-direction is destroyed.It is also found that the distortions of pseudo-Kossel lines arising from high Bragg angle diffraction planes are smaller than those arising from lower angle diffraction planes.