TRANSMISSION ELECTRON-MICROSCOPY OF LEAD SCANDIUM TANTALATE THIN-FILMS

Preliminary results are reported on the examination of lead scandium tantalate (PST) ferroelectric thin‐films by transmission electron microscopy (TEM). The samples were grown on sapphire substrates by the solution‐gel route and were examined in both plan and transverse section. Scanning electron micrographs of the surface of the samples of PST on sapphire showed that the PST films were invariably cracked. TEM examination of the PST on sapphire in plan section revealed that two distinct distributions of PST grains had grown on the sapphire (100 and 1500 nm diameter) and that nucleation of PST on the sapphire surface was associated with surface flaws and dislocations. TEM samples prepared in transverse section revealed that ordering of the Sc and Ta cations was greater at the PST‐sapphire interface than within the interior of the thin‐film. Small crystallites of an unidentified second phase were also observed to have formed in the centres of PST grains. 1990 Blackwell Science Ltd