ELECTRON-MICROSCOPY STUDY OF THE DOMAIN-STRUCTURE IN THE FERROELASTIC PHASE OF LEAD PHOSPHATE PB3(PO4)2

Electron microscopy techniques have been used to reveal the ferroelastic domain structure of Pb//3(PO//4)//2. Ferroelastic domains are found separated by walls whose thickness is less than 50 A. For the first time, the antiphase boundaries expected following the space symmetry change at the phase transition have been directly revealed. New results on the geometry of the domain pattern is reported and discussed: in particular a new kind of zig-zag domain was observed.