SYNCHROTRON X-RAY TOPOGRAPHY STUDY OF ER-DOPED LAP5O14 CRYSTAL

An Er-doped LaP5O14 ferroelastic crystal has been studied by synchrotr on radiation white beam x-ray topography. A set of normal ferroelastic domains is revealed in topographs by the intense contrast at the doma in walls and the temperature dependence of the wall contrast is shown to be in good agreement with that expected from the structural conside ration. In addition to growth bands and growth sector boundaries, a ty pe of abnormal boundary is observed, and the contrast varies with the occurrence of phase transitions. A detailed discussion on experimental results is given in terms of structural and symmetry analyses.