Microstructure and phase transitions in Pb(Sc0.5Ta0.5)O-3

The microstructure and phase transitions in the perovskite-based ferroelect ric lead scandium tantalate, Pb(Sc0.5Ta0.5)O-3 have been investigated by tr ansmission electron microscopy. The effects of ordering of Sc and Ta cation s are apparent in reciprocal space as well as in direct space images. High- resolution observations allow direct structure imaging of the domain struct ure. The structure of the low temperature ferroelectric phase is studied by selected area electron diffraction (SAED) and electron microdiffraction. T he relaxer behaviour of this paraelectric-ferroelectric transition is displ ayed by diffuse intensities in the SAED patterns at temperatures around the Curie point.