Domain structure of LiCsSO4 crystal studied by 7Li and 133Cs NMR

The growth twin-domain structure of a LiCsSO4 single crystal grown by slow evaporation has been investigated using Li-7 and Cs-133 nuclear magnetic resonance (NMR) at room temperature. Instead of simple one set signals due to quadrupole interaction, three sets of NMR signals were obtained. The obtained results can be explained by the existence of three kinds of growth twin-domains, rotated with respect to each other by 60 degrees around the c-axis. Experimental results show that the equations of the growth twin boundaries belong to the 6/mmmFmmm ferroelastic species. Thus, the symmetry of the hypothetical prototypic phase of the LiCsSO4 crystal is 6/mmm. (C) 1999 Elsevier Science Ltd. All rights reserved.