Bragg-regime diffraction of light by twinned orthorhombic domains

Abstract

Optical Bragg-regime diffraction of lighi from the domain structure of a twinned orthorhombic crystal is reported for the first time. Diffracted beams were observed in Dy AsO,, DyVO,. TbV04, and some mixed crystals below their orthorhombic phase transitions. The diffracted beams could be seen over a range of scattering angles, with peak intensity near 5' corresponding to an average domain spacing of about 3pm. The temperature-dependent intensity was measured to obtain values for the 0rder.parameter critical exponent

Cooperative Jahn-Teller induced phase transition of TbVO4: single crystal structure analyses of the tetragonal high temperature phase and the twinned orthorhombic phase below 33 K

“…An interesting experiment using Bragg-regime diffraction of light originated by the twin interface (Reza and Taylor 1991) not only showed the periodic reoccurrence of this interface †, it also determined the size of the domains to be of the order of 4. In both phases the Tb atom is coordinated by eight O atoms to form a triangular dodecahedron (figure 2).…”