SEEDING ACCELERATION OF PEROVSKITE CRYSTALLIZATION IN LEAD CALCIUM TITANATE THIN-FILMS

Seeding to enhance the kinetics of phase transformation was demonstrat ed with a special seeding process using crystallized ultrafine lead ti tanate powder to lower the temperature of perovskite formation of the modified lead calcium titanate thin films. X-ray diffraction and scann ing electron microscopy show that the pyrochlore-to-perovskite phase t ransformation temperature of the seeded lead calcium titanate film can be lowered by as much as 50 degrees C when compared with the unseeded lead calcium titanate film. This is most likely related to the decrea se of activation energies of nucleation which, in turn, increases the kinetics of the perovskite formation, since numerous nucleation sites are provided. The similarity, or small lattice mismatch of crystal str ucture between the lead titanate and perovskite of the modified lead c alcium titanate film supports these explanations. (C) 1997 Elsevier Sc ience B.V.